CBSE Class 7 Science Revision Worksheet Set 17

Chapter 7 : Weather, Climate and Adaptations of animals to climate :

Fill in the blanks :

1. ______________ is the measure of moisture in air.

2. The weather reports are prepared by the ___________ department of the government.

3. The day today condition of the atmosphere is a place is called ____________ at that place.

4. The maximum temperature of the day occurs in the ___________ while minimum temperature occurs in the ______________.

5. Polar regions are situated near ___________ and tropical region is situated around the _______________.

6. Special features of an animal to live in its surrounding is called _______________

7. Penguins are good swimmer because their bodies are___________ and their feet have __________________.

8. All the changes in the weather are driven by the ______________

9. One of the important feature of tropical region is __________

10. The ___________ regions are very cold throughout the year.

11. The temperature, humidity, rainfall and other factors are called _____________________ of the weather.

12. The typical desert climate is ___________ and _____________.

13. The climate of the north-east of India is __________________

14. _____________ is a means which is adapted by some birds to escape the harsh, cold conditions.

Name the following

1. An instrument used to measure rainfall.

2. The thermometer used to record maximum and minimum temperature.

3. Two animals living in polar regions.

Topic : Flow of Heat

Very Short Question/Answers-

Question 1 By which mode is heat transferred in solids?
Answer : In solids, heat is transferred through the process of conduction. This is because the molecules in solids are rigid and only vibrate on heating rather than moving from one place to the other. The vibrating molecules of the hotter region hit those molecules in the colder region, causing the transfer of heat.

Question 2: Are most metals good or bad conductors of heat?
Answer : Most metals are good conductors of heat. This is because the molecules in metals vibrate and hit the nearby molecules to transfer the heat energy, rather than moving from one place to the other.

Question 3: Gases are insulators of heat. True of false?
Answer : True Gases are insulators of heat because their molecules are loosely bonded; hence, they do not conduct heat.

Question 4: By which mode is heat transferred in liquids?
Answer : Heat transfer in liquids takes place through the process of convection. In this case, the molecules of liquids move from one place to other to transfer the heat energy.

Question 5: Name a liquid which is a good conductor of heat.
Answer : Mercury is a liquid which is a good conductor of heat. It is an exception, as all liquids are good insulator of heat.

Question 6: When you heat water in a pan, by which mode does most of the heat travel in water-conduction, convection or radiation?
Answer : When we heat water in a pan, the heat travels throughout the water through the process of convection.

Question 7: In which mode of transfer of heat does the medium not get heated up?
Answer : Radiation is a process in which the molecules don't transfer or carry heat from the hotter to colder regions, but the material itself radiates the heat energy. Therefore, it requires no medium to transfer the heat. Higher the temperature of the body, the more it radiates heat.

Question 8: A thermos flask consists of a double-walled glass vessel with the space between them filled with air, which is a bad conductor of heat. True of flase?
Answer : False. In a thermos flask, the space between the two glass walls is empty. This vacuum prevents heat loss through conduction and convection, as there is no medium present to transfer the heat by these two processes.

Question 9: Radiant heat falling on a body is partly absorbed and partly __________. Some of it may also be__________
Answer : Radiant heat falling on a body is partly absorbed and partly reflected. Some of it may also get transmitted.

Please click the below link to access CBSE Class 7 Science - Revision (8)

Chapter 7: Weather, Climate and Adaptations of Animals to Climate

Fill in the Blanks

Question 1. ______________ is the measure of moisture in air.
Answer: Humidity
In simple words: Humidity tells us how much water vapor is present in the air.

Exam Tip: High humidity makes sweat dry slowly, causing us to feel sticky.

Question 2. The weather reports are prepared by the ___________ department of the government.
Answer: Meteorological
In simple words: The Meteorological Department studies atmospheric conditions and issues daily weather forecasts.

Exam Tip: Spell "Meteorological" correctly to avoid losing marks.

Question 3. The day today condition of the atmosphere is a place is called ____________ at that place.
Answer: weather
In simple words: Weather describes the daily atmospheric state at a particular location.

Exam Tip: Unlike climate, weather can change quickly within a few hours.

Question 4. The maximum temperature of the day occurs in the ___________ while minimum temperature occurs in the ______________.
Answer: afternoon, early morning
In simple words: Days feel hottest during the afternoon and coldest at dawn.

Exam Tip: The minimum temperature is recorded around sunrise, not at midnight.

Question 5. Polar regions are situated near ___________ and tropical region is situated around the _______________.
Answer: the poles, equator
In simple words: Polar zones sit near the North and South Poles, while tropics lie around the equator.

Exam Tip: Tropical areas stay warm because sunlight falls directly over the equator.

Question 6. Special features of an animal to live in its surrounding is called _______________
Answer: adaptation
In simple words: Adaptations are body features or habits that help an animal survive in its home.

Exam Tip: Adaptations develop over thousands of years to suit specific habitats.

Question 7. Penguins are good swimmer because their bodies are___________ and their feet have __________________.
Answer: streamlined, webs
In simple words: Sleek bodies and webbed feet help penguins paddle smoothly through water.

Exam Tip: Streamlined bodies reduce water resistance while swimming.

Question 8. All the changes in the weather are driven by the ______________
Answer: sun
In simple words: Solar energy heats the Earth unevenly, causing wind, clouds, and weather changes.

Exam Tip: The sun is the primary engine behind all weather phenomena on Earth.

Question 9. One of the important feature of tropical region is __________
Answer: hot and humid climate
In simple words: Tropical regions stay warm and receive generous rainfall throughout the year.

Exam Tip: Tropical rainforests support a rich variety of plants and wildlife.

Question 10. The ___________ regions are very cold throughout the year.
Answer: polar
In simple words: Polar zones remain covered in snow and ice during all seasons.

Exam Tip: Temperatures in polar regions can drop below -37 °C during winter.

Question 11. The temperature, humidity, rainfall and other factors are called _____________________ of the weather.
Answer: elements
In simple words: Heat, air moisture, rain, and wind are called the elements of weather.

Exam Tip: Wind speed and atmospheric pressure are also key weather elements.

Question 12. The typical desert climate is ___________ and _____________.
Answer: hot, dry
In simple words: Deserts experience high temperatures and receive very little rainfall.

Exam Tip: Sand heats up rapidly during daylight and cools off quickly at night.

Question 13. The climate of the north-east of India is __________________
Answer: wet
In simple words: Northeastern India receives rain for major parts of the year, making its climate wet.

Exam Tip: Cherrapunji and Mawsynram in the northeast receive exceptionally heavy rainfall.

Question 14. _____________ is a means which is adapted by some birds to escape the harsh, cold conditions.
Answer: Migration
In simple words: Migration is the seasonal flight of birds to warmer places to escape extreme winter.

Exam Tip: Siberian cranes migrate to Bharatpur in Rajasthan every winter.

Name the Following

Question 1. An instrument used to measure rainfall.
Answer: Rain gauge
In simple words: A rain gauge collects rainwater in a measuring tube to find rainfall depth.

Exam Tip: Rainfall measurements are recorded in millimeters.

Question 2. The thermometer used to record maximum and minimum temperature.
Answer: Maximum-minimum thermometer
In simple words: This thermometer tracks the highest and lowest temperatures of the day.

Exam Tip: It is also known as Six's maximum-minimum thermometer.

Question 3. Two animals living in polar regions.
Answer: Polar bear and penguin
In simple words: Polar bears and penguins are adapted to survive in freezing polar ice.

Exam Tip: Arctic foxes, seals, and reindeer are also correct examples.

Question 4. Two animals living in tropical regions.
Answer: Red-eyed tree frog and lion-tailed macaque
In simple words: Tree frogs and macaques live in warm, green tropical rainforests.

Exam Tip: Monkeys, elephants, and tigers are other common tropical animals.

Question 5. Two animals with ability to camouflage with the surroundings.
Answer: Chameleon and stick insect
In simple words: Chameleons and stick insects match their background colors to hide from enemies.

Exam Tip: Polar bears also use camouflage by blending their white fur with snow.

Choose the Correct Answer

Question 1. Long tailed macaque is also known as (Beard ape / Monkey)
Answer: Beard ape
In simple words: The lion-tailed macaque has a silver mane that looks like a beard.

Exam Tip: It spends most of its life high up in rainforest tree canopies.

Question 2. (Weather / Climate) changes frequently.
Answer: Weather
In simple words: Weather changes from hour to hour, while climate remains steady over decades.

Exam Tip: Climate represents an average over roughly 25 years.

Question 3. Tusks of elephants are modified (teeth/bones)
Answer: teeth
In simple words: Elephant tusks are enlarged upper front teeth.

Exam Tip: Tusks are modified incisors used to strip tree bark and fight off rivals.

Write True or False

Question 1. Mammals, many types of fish and insects are also known to migrate seasonally. ________
Answer: True
In simple words: Whales, salmon, and butterflies travel across regions with changing seasons.

Exam Tip: Monarch butterflies fly thousands of miles to escape cold winters.

Question 2. Polar regions doesn’t see the sun for six months. _____________
Answer: True
In simple words: Earth's tilt keeps the poles dark for six continuous months in winter.

Exam Tip: For the other six months, the sun remains above the horizon continuously.

Question 3. Days are longer than nights in winter. ___________
Answer: False
In simple words: Winter has shorter daytime hours and longer nights.

Exam Tip: Days are longer than nights during summer.

Define the Following

Question. > Weather
Answer: Weather is the day-to-day state of the atmosphere at a given place regarding temperature, humidity, rainfall, and wind speed.
In simple words: Weather tells us what the outdoor air is like right now.

Exam Tip: Mention at least three elements: temperature, humidity, and rainfall.

Question. > Climate
Answer: Climate is the average weather pattern recorded at a place over a long period, typically about 25 years.
In simple words: Climate is the usual weather pattern of a region observed over decades.

Exam Tip: Mention the benchmark duration of roughly 25 years.

Question. > Adaptation.
Answer: Adaptation is any physical characteristic or habit that helps an organism survive and thrive in its natural environment.
In simple words: Adaptations are body tools that help animals stay alive in their habitats.

Exam Tip: Adaptations can be structural (like fur) or behavioral (like migration).

Lesson 8: Winds, Storms and Cyclones

Fill in the Blanks

Question 1. _____________________ around us exerts pressure.
Answer: Air
In simple words: The air surrounding us presses down on everything with atmospheric pressure.

Exam Tip: A crushed tin can experiment demonstrates that air exerts pressure.

Question 2. Difference of temperature between two regions sets ___________ in air.
Answer: convection currents
In simple words: Temperature differences cause warm air to rise and cool air to flow in, creating currents.

Exam Tip: Convection currents are the primary cause of wind motion.

Question 3. Increased wind speed is accompanied by __________ air pressure.
Answer: reduced (lower)
In simple words: Fast-blowing wind lowers the air pressure in that area.

Exam Tip: High-speed winds can blow roofs away because air pressure above the roof drops.

Question 4. Air moves from the region where the air pressure is _________ to the region where the pressure is _______________.
Answer: high, low
In simple words: Air always flows from high-pressure zones toward low-pressure pockets.

Exam Tip: The greater the pressure difference, the faster the air rushes.

Question 5. Air _______________on heating and __________ on cooling.
Answer: expands, contracts
In simple words: Air swells up when warm and shrinks when cold.

Exam Tip: Warm air expands, becomes lighter (less dense), and rises.

Question 6. The warm air is ____________ than the cold air.
Answer: lighter
In simple words: Warm air weighs less than cold air, so it floats upward.

Exam Tip: Smoke rises because it consists of warm, low-density air.

Question 7. Uneven heating on the earth is the main cause of ______________
Answer: wind currents
In simple words: Unequal solar heating across the globe generates global wind currents.

Exam Tip: The equator heats up more than the poles, driving wind circulation.

Question 8. Winds carrying ______________ bring rain.
Answer: water vapour
In simple words: Clouds form when moist winds carry water vapor from seas onto land.

Exam Tip: Monsoon winds carry abundant water vapor from the oceans.

Question 9. The word monsoon is derived from the Arabic word ___________ which means season.
Answer: 'mausam'
In simple words: Monsoon comes from the Arabic word "mausam", meaning season.

Exam Tip: Monsoon winds reverse their flow direction with the change of seasons.

Question 10. The monsoon winds carry ____________ and it rains.
Answer: water (moisture)
In simple words: Moisture-packed monsoon winds create clouds that bring seasonal rainfall.

Exam Tip: Summer monsoons carry moisture from the southwest Indian Ocean over India.

Question 11. Falling water droplets along with rising air create lightning and sound and is known as _______________
Answer: thunderstorm
In simple words: Strong upward air currents with falling rain create thunder and lightning flashes.

Exam Tip: Thunderstorms develop frequently in hot, humid tropical regions.

Question 12. High speed winds and air pressure difference can cause ________________________
Answer: cyclones
In simple words: Huge spinning storm systems caused by low pressure and fast winds are cyclones.

Exam Tip: Cyclones produce torrential rainfall and massive ocean storm surges.

Question 13. The calm area in the centre of a cyclone is called __________
Answer: eye
In simple words: The peaceful, cloudless center of a spinning cyclone is called its eye.

Exam Tip: The eye has low air pressure, light winds, and no clouds.

Question 14. A cyclone is called a _______________ in the American continent and _____________in Japan and Philippines.
Answer: hurricane, typhoon
In simple words: Cyclones are called hurricanes in the Americas and typhoons in Japan and the Philippines.

Exam Tip: Hurricanes, typhoons, and cyclones are regional names for tropical cyclones.

Name the Following

Question 1. A dark funnel shaped cloud that reaches from the sky to the ground.
Answer: Tornado
In simple words: A tornado is a twisting, funnel-shaped storm cloud that sweeps across the ground.

Exam Tip: Winds inside a violent tornado can exceed 300 km/h.

Question 2. The instrument that measures the wind speed
Answer: Anemometer
In simple words: An anemometer uses spinning cups to measure how fast the wind is moving.

Exam Tip: A wind vane shows wind direction, while an anemometer measures wind speed.

Question 3. Two modern technologies that help us to monitor cyclones.
Answer: Satellites and weather radars
In simple words: Space satellites and radar stations help meteorologists track cyclones in advance.

Exam Tip: Cyclone alerts are issued 48 hours before an expected storm.

Question 4. The coastline of India that is more vulnerable to cyclones.
Answer: Eastern coastline
In simple words: India's eastern coast along the Bay of Bengal experiences more cyclones.

Exam Tip: States like Odisha, Andhra Pradesh, and Tamil Nadu are frequently affected.

Define the Following

Question 1. Cyclone
Answer: A cyclone is a massive, violently rotating weather system formed over warm ocean waters, centered around low pressure and surrounded by fast winds.
In simple words: A cyclone is a giant spinning ocean storm with heavy rain and destructive winds.

Exam Tip: Heat released when water vapor condenses fuels the energy of a cyclone.

Question 2. Tornado
Answer: A tornado is a violent, spinning column of air shaped like a dark funnel that extends from a storm cloud to touch the earth.
In simple words: A tornado is a twisting wind funnel that destroys objects on the ground.

Exam Tip: Tornadoes suck debris, dust, and cars into their vortex.

Question 3. Thunderstorm
Answer: A thunderstorm is an intense local storm featuring warm rising air, falling rain, flashing lightning, and loud thunder.
In simple words: A thunderstorm brings heavy rain, bright lightning flashes, and booming thunder.

Exam Tip: Never seek shelter under an isolated tall tree during a thunderstorm.

Choose the Correct Answer

Question 1. In India, monsoon wind blows in south west direction in (summer/winter).
Answer: summer
In simple words: Southwest monsoon winds bring rain to India during summer.

Exam Tip: Land warms faster than the ocean in summer, drawing winds from the southwest.

Question 2. In winter, the direction of wind is from (land to ocean/ocean to land).
Answer: land to ocean
In simple words: Cold winter winds blow outward from the land toward the ocean.

Exam Tip: These winter winds are dry because they originate over land.

Question 3. A cyclone watch is issued ( 24/48 ) hours in advance of any expected storm.
Answer: 48
In simple words: A cyclone alert or watch is announced 48 hours before the storm arrives.

Exam Tip: A cyclone warning is issued 24 hours in advance.

Question 4. (Thunderstorms/tornadoes) are frequent in India.
Answer: Thunderstorms
In simple words: Thunderstorms happen frequently in warm tropical India, whereas tornadoes are rare.

Exam Tip: High tropical humidity in India provides ideal conditions for thunderstorms.

LN. 9 : SOIL

I. Fill in the Blanks

Question 1. The rotting dead matter in the soil is called __________________.
Answer: humus
In simple words: Decomposed plant and animal remains form dark, fertile humus.

Exam Tip: Humus improves soil texture and provides essential nutrients for plant growth.

Question 2. A vertical section through different layers of the soil is called _______________.
Answer: soil profile
In simple words: A vertical cut showing all soil layers from top to bedrock is a soil profile.

Exam Tip: Each layer in a soil profile is called a horizon (A, B, C, and bedrock).

Question 3. The mixture of _____________ and humus is called the soil.
Answer: rock particles
In simple words: Soil is made of weathered rock fragments mixed with organic humus.

Exam Tip: Both mineral particles and organic matter are needed to make fertile soil.

Question 4. Percolation rate of water is the highest in the ____________ soil and least in the ___________ soil.
Answer: sandy, clayey
In simple words: Water trickles down fastest through sand and slowest through clay.

Exam Tip: Sandy soil has big air spaces, allowing rapid percolation of water.

Question 5. The best top soil for growing plants is _____________.
Answer: loamy soil
In simple words: Loamy soil balances water retention and aeration, making it best for crops.

Exam Tip: Loam is a balanced mixture of sand, clay, silt, and humus.

Question 6. The removal of land surface by water, wind or ice is known as __________.
Answer: soil erosion
In simple words: The loss of topsoil carried away by wind or rain is called soil erosion.

Exam Tip: Plant roots anchor soil particles firmly, preventing erosion.

II. Write True or False

Question 1. If the amount of large and fine particles is about the same, then the soil is called loamy soil.
Answer: True
In simple words: Loamy soil contains roughly equal proportions of large and fine particles.

Exam Tip: This balance gives loam good moisture retention and proper airflow.

Question 2. The layer which is hard and difficult to dig with spade is called top soil.
Answer: False
In simple words: Topsoil is soft and easy to dig; the bedrock or C-horizon is hard.

Exam Tip: Topsoil (A-horizon) is porous and soft, making it easy to dig.

Question 3. Sandy soil is used to make pots, toys and statues.
Answer: False
In simple words: Potters use sticky clayey soil to mold pots and statues, not sandy soil.

Exam Tip: Clayey soil is sticky when wet, which allows it to be shaped easily.

Question 4. Soil is affected by climatic factors.
Answer: True
In simple words: Rainfall, temperature, and wind influence soil formation and quality.

Exam Tip: Climatic factors speed up or slow down the weathering of rocks.

Question 5. The soil which is light, well aerated and rather dry is clayey soil.
Answer: False
In simple words: Sandy soil is light and dry; clayey soil is heavy and holds water.

Exam Tip: Large particle gaps make sandy soil light and well-aerated.

Question 6. In deserts, soil erosion occurs through wind.
Answer: True
In simple words: Strong desert winds blow away dry, loose sand because there are few plants.

Exam Tip: Lack of vegetation makes dry desert soils prone to wind erosion.

Question 7. Cotton is grown in sandy loam soil.
Answer: True
In simple words: Cotton crops thrive in sandy loam and black soils that drain water easily.

Exam Tip: Cotton requires well-drained soil with good air space for root growth.

Question 8. Soil erosion takes place in areas of heavy vegetation.
Answer: False
In simple words: Dense plant roots bind the soil, preventing erosion.

Exam Tip: Erosion occurs primarily on bare, deforested ground.

III Name the Following

Question 1. Two agents of weathering.
Answer: Wind and water
In simple words: Wind and flowing water break rocks into small soil pieces.

Exam Tip: Temperature changes and ice also act as weathering agents.

Question 2. The uppermost layer of soil.
Answer: Topsoil (A-horizon)
In simple words: The top layer of soil is rich in humus and feeds plant roots.

Exam Tip: Topsoil is dark in color due to its high organic matter content.

Question 3. The type of soil that can hold more water.
Answer: Clayey soil
In simple words: Clayey soil has tiny spaces that trap water tightly.

Exam Tip: Its high water-holding capacity makes clayey soil ideal for growing paddy.

Question 4. The soil which is a mixture of sand, clay and silt.
Answer: Loamy soil
In simple words: Loam is a blend of sand, clay, and silt that supports crops.

Exam Tip: Silt particles have a size between those of sand and clay.

Question 5. Three agents of soil erosion.
Answer: Wind, water, and ice
In simple words: Strong winds, running water, and sliding glaciers wash or blow topsoil away.

Exam Tip: Human deforestation is a major indirect driver of soil erosion.

IV Define the Following

Question 1. Soil
Answer: Soil is the loose, uppermost layer of the Earth's crust consisting of weathered rock particles, minerals, and organic humus that supports plant life.
In simple words: Soil is the mixture of broken rock grains and rotten leaves that covers the ground.

Exam Tip: Mention both mineral particles and humus in your definition.

Question 2. Weathering
Answer: Weathering is the natural process of breaking down large rocks into smaller pieces through the action of wind, water, and climate over time.
In simple words: Weathering is the slow crumbling of rocks caused by weather.

Exam Tip: Weathering takes hundreds to thousands of years to produce topsoil.

Question 3. Soil Profile
Answer: A soil profile is a vertical section through the ground that displays the distinct horizontal layers (horizons) of soil.
In simple words: A soil profile is a vertical cut showing all soil layers down to bedrock.

Exam Tip: The main horizons in a soil profile are A-horizon, B-horizon, C-horizon, and bedrock.

CHAPTER 10 : RESPIRATION IN ORGANISMS.

I. Fill in the Blanks

Question 1. Breathing is a part of _________________.
Answer: respiration
In simple words: Breathing is the physical step of taking in oxygen within the overall respiration process.

Exam Tip: Respiration includes both physical breathing and chemical energy release inside cells.

Question 2. Breathing involves the movement of the ___________ and ______________.
Answer: diaphragm, rib cage
In simple words: When we breathe, our chest ribs and sheet-like diaphragm move together.

Exam Tip: During inhalation, ribs move up and outward while the diaphragm moves down.

Question 3. The food has ____________ which is released during respiration.
Answer: stored energy
In simple words: Respiration breaks down digested food to release energy for body activities.

Exam Tip: Glucose is broken down with oxygen to release this chemical energy.

Question 4. The accumulation of ___________ causes muscle cramps.
Answer: lactic acid
In simple words: Fast running without enough oxygen makes muscles produce painful lactic acid.

Exam Tip: A warm bath or massage improves circulation and breaks down lactic acid.

Question 5. Yeast can survive in absence of oxygen, they are called ___________.
Answer: anaerobes
In simple words: Organisms that live and respire without needing air are called anaerobes.

Exam Tip: Yeast releases alcohol and carbon dioxide during anaerobic respiration.

Question 6. The taking in of air rich in oxygen into the body is called ____________.
Answer: inhalation
In simple words: Inhaling means drawing oxygen-rich air into the lungs.

Exam Tip: Breathing out air rich in carbon dioxide is called exhalation.

Question 7. _____________is the food which is broken down in respiration to release energy.
Answer: Glucose
In simple words: Cells break down simple glucose sugar to supply energy for living.

Exam Tip: Glucose combines with oxygen to produce carbon dioxide, water, and energy.

II. Write True or False

Question 1. Cellular respiration takes place in all the cells of living organisms.
Answer: True
In simple words: Every living cell performs respiration to generate usable energy.

Exam Tip: Cellular respiration takes place inside microscopic cell structures called mitochondria.

Question 2. All living organisms respire to get energy from food.
Answer: True
In simple words: Living things respire because cells require energy from food to stay alive.

Exam Tip: Without respiration, food energy cannot be made available to living cells.

Question 3. Our muscle cells do anaerobic respiration only when there is temporary deficiency of oxygen.
Answer: True
In simple words: Heavy sprinting creates a brief oxygen shortage, so muscles respire without oxygen.

Exam Tip: This temporary anaerobic mode produces lactic acid.

Question 4. Breathing involves the movement of the diaphragm and the rib cage.
Answer: True
In simple words: Moving the ribs and diaphragm expands and shrinks the chest to move air.

Exam Tip: The diaphragm is a large, dome-shaped muscle below the lungs.

Question 5. Whales and dolphins have gills for breathing.
Answer: False
In simple words: Whales and dolphins are mammals with lungs, and they breathe through blowholes at the surface.

Exam Tip: Unlike fish, marine mammals do not have gills.

Question 6. Gills are projections of the skin.
Answer: True
In simple words: Gills in fish are thin, blood-rich skin folds that take dissolved oxygen from water.

Exam Tip: Gills are heavily supplied with blood vessels for rapid gas exchange.

Question 7. The percentage of carbon dioxide is higher in inhaled air in comparision to exhaled air.
Answer: False
In simple words: Exhaled air contains about 4.4% carbon dioxide, which is much higher than the 0.04% in inhaled air.

Exam Tip: Inhaled air is higher in oxygen (21%), while exhaled air has more carbon dioxide.

Question 8. We often feel hungry after a physical exercise.
Answer: True
In simple words: Working out burns food energy rapidly, signaling our body that it needs more food.

Exam Tip: Faster respiration during exercise consumes glucose quickly.

Question 9. Increased physical activity reduces the rate of breathing.
Answer: False
In simple words: Heavy activity makes breathing much faster to supply extra oxygen to working muscles.

Exam Tip: Breathing rate increases from a resting 15-18 breaths per minute up to 25 breaths per minute during exercise.

Question 10. Elephants, snakes and birds have lungs for breathing.
Answer: True
In simple words: Terrestrial vertebrates like mammals, reptiles, and birds breathe using lungs.

Exam Tip: All land animals possess lungs in their chest cavity for breathing.

III. Define the Following

Question 1. Breathing .
Answer: Breathing is the physical act of inhaling oxygen-rich air and exhaling carbon dioxide-rich air with the help of respiratory organs.
In simple words: Breathing is drawing air in and blowing air out through your lungs.

Exam Tip: Breathing is a mechanical process, whereas respiration is a chemical process.

Question 2. Cellular respiration.
Answer: Cellular respiration is the biochemical breakdown of glucose in living cells using oxygen to release energy, water, and carbon dioxide.
In simple words: Cells break down food inside themselves to produce energy for living.

Exam Tip: Write the equation: Glucose + Oxygen → Carbon dioxide + Water + Energy.

IV. Name the Following

Question 1. Tiny pores on the surface of leaves for exchange of gases.
Answer: Stomata
In simple words: Stomata are tiny leaf pores that let oxygen and carbon dioxide pass in and out.

Exam Tip: Stomata are regulated by surrounding guard cells.

Question 2. An organism with tracheal system.
Answer: Cockroach
In simple words: Cockroaches breathe using an internal network of air tubes called tracheae.

Exam Tip: Insects breathe through spiracles connected to a tracheal tube system.

Question 3. Skeletal structures surrounding the chest cavity.
Answer: Ribs (Rib cage)
In simple words: Curved rib bones form a protective cage around the lungs and heart.

Exam Tip: Humans have 12 pairs of ribs enclosing the thoracic cavity.

Question 4. An aerobic organism .
Answer: Human (or dog, horse)
In simple words: Aerobic organisms require oxygen to survive and release food energy.

Exam Tip: Most plants and animals are obligate aerobes.

Question 5. The breathing organ of earthworm .
Answer: Moist skin
In simple words: Earthworms absorb oxygen directly through their slimy, moist skin.

Exam Tip: An earthworm's skin must stay wet with mucus for gas exchange to occur.

Question 6. The openings through which we inhale.
Answer: Nostrils
In simple words: Nostrils are the nose holes where air enters our breathing passage.

Exam Tip: Tiny hairs and mucus inside nostrils trap airborne dust.

Question 7. The anaerobic organism used in production of beer and wine.
Answer: Yeast
In simple words: Single-celled yeast ferments sugar into alcohol without needing oxygen.

Exam Tip: Yeast fermentation also produces carbon dioxide, which makes bread dough rise.

V. Answer the Following

Question 1. Why do all animals respire? -2marks.
Answer: Animals need a continuous supply of energy to carry out life processes such as movement, digestion, growth, and tissue repair. Respiration breaks down the food consumed by the animal to release this vital energy. Without respiration, cells cannot function, and the organism cannot survive.
In simple words: Animals respire to extract energy from digested food to stay alive.

Exam Tip: Mention that respiration releases the chemical energy stored in food.

Question 2. Describe the mechanism of breathing in humans. -5marks.
Answer: The breathing mechanism involves two coordinated phases driven by chest muscle and diaphragm movements:
1. Inhalation: The rib muscles contract, moving the rib cage upward and outward. At the same time, the flat muscular diaphragm moves downward. This increases the space inside the chest cavity, lowering internal air pressure. Atmospheric air rushes through the nostrils, trachea, and bronchi to fill the expanding lungs.
2. Exhalation: The rib muscles relax, letting the rib cage move downward and inward. The diaphragm relaxes and curves upward back to its dome shape. This decreases chest volume, raising air pressure inside the lungs and pushing carbon dioxide-rich air out of the body.
In simple words: When the diaphragm moves down and ribs lift, air rushes in; when they relax, air is pushed out.

Exam Tip: Describe both inhalation and exhalation clearly, focusing on rib and diaphragm movements.

Question 3. Describe the process of respiration in cockroach. -5marks.
Answer: A cockroach respires using a specialized network of internal air tubes:
1. Spiracles: Small openings called spiracles run along the sides of the cockroach's body.
2. Tracheal tubes: These openings connect to a branching network of air tubes called tracheae that spread throughout the insect's body.
3. Gas Exchange: Oxygen-rich air enters through the spiracles, travels through the tracheal tubes, and diffuses directly into body cells. Carbon dioxide from the cells diffuses back into the tracheae and leaves the body through the spiracles.
In simple words: Cockroaches take in air through side holes called spiracles that connect to tiny air pipes leading to every cell.

Exam Tip: Highlight the terms "spiracles" and "tracheal system" for full marks.

VI. Draw and Label

Question 1. The human respiratory system.
Answer: The human respiratory system consists of the nasal cavity, pharynx, trachea (windpipe), bronchi, and two spongy lungs enclosed within the rib cage above the diaphragm.

In simple words: Air travels down the windpipe into two lungs sitting right above the diaphragm muscle.

Exam Tip: Be sure to label the trachea, bronchi, lungs, and diaphragm clearly.

Chapter 11: Transportation in Animals and Plants

Fill in the Blanks

Question 1. The fluid part of blood is called ______________.
Answer: plasma
In simple words: Plasma is the yellowish liquid part of blood that carries blood cells.

Exam Tip: Plasma makes up about 55% of total blood volume.

Question 2. Blood is red in colour due to the presence of a pigment called _________.
Answer: haemoglobin
In simple words: Haemoglobin is an iron-rich protein that gives blood its red color.

Exam Tip: Haemoglobin binds with oxygen to transport it to cells throughout the body.

Question 3. The ___________ cells in our body fight against germs.
Answer: white blood (WBC)
In simple words: White blood cells protect the body by fighting off infections and germs.

Exam Tip: White blood cells act like the body's defense soldiers.

Question 4. ___________ help in clotting of blood.
Answer: Platelets
In simple words: Platelets form scabs over cuts to stop bleeding.

Exam Tip: A clot forms a plug that prevents excessive blood loss.

Question 5. The number of heart beats per minute is called _______________.
Answer: pulse rate (heart rate)
In simple words: Pulse rate measures how many times your heart pumps in one minute.

Exam Tip: A resting adult has a normal pulse rate of 72 to 80 beats per minute.

Question 6. The waste dissolved in water is removed as ______________.
Answer: urine
In simple words: Kidneys filter liquid waste and excess water out of the blood as urine.

Exam Tip: An adult human normally passes 1 to 1.8 liters of urine daily.

Question 7. The filtering of blood through an artificial kidney is called _____________.
Answer: dialysis
In simple words: Dialysis is a machine treatment that cleans the blood when kidneys stop working.

Exam Tip: Patients suffering from kidney failure undergo periodic dialysis.

Question 8. Salts and urea is removed along with water as ______________.
Answer: sweat
In simple words: Sweat helps cool the body while washing away small amounts of salt and urea.

Exam Tip: Evaporating sweat cools the skin on hot summer days.

Question 9. _________________ carry blood from the heart to all parts of the body.
Answer: Arteries
In simple words: Thick-walled arteries carry freshly pumped oxygenated blood away from the heart.

Exam Tip: Arteries have thick, elastic walls to withstand high pumping pressure.

Question 10. ________________ carry blood from all parts of the body to the heart.
Answer: Veins
In simple words: Veins bring used, deoxygenated blood back toward the heart.

Exam Tip: Veins contain internal valves to prevent blood from flowing backward.

Question 11. ___________________ is the instrument to amplify the sound of the heart.
Answer: Stethoscope
In simple words: Doctors use a stethoscope to listen clearly to heartbeats.

Exam Tip: A stethoscope has a sensitive chest piece, earpieces, and a connecting tube.

Name the Following

Question 1. The organ which pumps blood.
Answer: Heart
In simple words: The heart is a muscular pump that circulates blood through vessels.

Exam Tip: The human heart is roughly the size of a clenched fist.

Question 2. The chambers of heart.
Answer: Right atrium, left atrium, right ventricle, and left ventricle
In simple words: The human heart has four rooms: two atria on top and two ventricles below.

Exam Tip: A muscular wall called the septum prevents oxygenated and deoxygenated blood from mixing.

Question 3. The scientist who discovered blood circulation.
Answer: William Harvey
In simple words: William Harvey was the English doctor who proved that blood circulates in closed loops.

Exam Tip: He published his famous discovery of blood circulation in 1628.

Question 4. The parts of excretory system.
Answer: Two kidneys, two ureters, a urinary bladder, and a urethra
In simple words: The urinary system includes kidneys, urine tubes, a storage bladder, and an exit pipe.

Exam Tip: Kidneys filter blood, ureters carry urine, the bladder stores it, and the urethra expels it.

Question 5. A group of cells that perform a particular function.
Answer: Tissue
In simple words: A tissue is a collection of similar cells working together on a shared job.

Exam Tip: Blood, muscle, and xylem are all examples of tissues.

Question 6. The vein which carries oxygen rich blood to the heart.
Answer: Pulmonary vein
In simple words: The pulmonary vein is the only vein carrying fresh oxygenated blood from lungs to heart.

Exam Tip: It is an exception to the rule that veins carry deoxygenated blood.

Question 7. The artery which carries carbon dioxide rich blood away from the heart.
Answer: Pulmonary artery
In simple words: The pulmonary artery takes deoxygenated blood from the heart to the lungs.

Exam Tip: It is an exception to the rule that arteries carry oxygenated blood.

Question 8. The vascular tissues in plants.
Answer: Xylem and phloem
In simple words: Xylem carries water up from roots, while phloem distributes food from leaves.

Exam Tip: These vascular bundles form the plumbing network of vascular plants.

Choose the Correct Answer

Question 1. Pulmonary (vein / artery ) carry pure blood.
Answer: vein
In simple words: Pulmonary veins deliver oxygen-rich blood from the lungs into the left atrium.

Exam Tip: Remember: Pulmonary vein = pure (oxygenated) blood.

Question 2. (Ammonia / urea ) is the excretory waste in fishes.
Answer: Ammonia
In simple words: Bony fish excrete toxic ammonia directly into surrounding water through their gills.

Exam Tip: Ammonia dissolves easily in large volumes of surrounding water.

Question 3. Phloem helps in the transport of (food / water)in plants.
Answer: food
In simple words: Phloem pipes distribute food sugars made in leaves to all plant organs.

Exam Tip: Useful mnemonic: Phloem for Food, Xylem for X-tra water.

Question 4. Birds excrete (urea / uric acid).
Answer: uric acid
In simple words: Birds produce a semi-solid white paste called uric acid to save body water.

Exam Tip: Excreting uric acid minimizes water loss for flight.

Question 5. ( Right / Left )side of the heart carries oxygen rich blood.
Answer: Left
In simple words: The left side handles fresh oxygenated blood, while the right side handles deoxygenated blood.

Exam Tip: The left ventricle has thicker muscle to pump oxygenated blood to the whole body.

Question 6. Blood is a (solid/liquid ) tissue.
Answer: liquid
In simple words: Blood is a fluid connective tissue made of liquid plasma and floating blood cells.

Exam Tip: Blood flows through vessels to transport gases, nutrients, and wastes.

Question 7. ( William Harvey / William Beaumont ) discovered the circulation of blood in humans.
Answer: William Harvey
In simple words: William Harvey discovered blood circulation; William Beaumont studied stomach digestion.

Exam Tip: Do not confuse Harvey (circulation) with Beaumont (stomach digestion).

Question 8. ( Photosynthesis /Transpiration ) is the process responsible for suction pull in plants.
Answer: Transpiration
In simple words: Water evaporating from leaves creates a suction pull that draws water up tall trees.

Exam Tip: Transpiration pull functions like sucking liquid upward through a drinking straw.

Write True or False

Question 1. WBC transports oxygen.
Answer: False
In simple words: Red blood cells (RBCs) carry oxygen with haemoglobin; WBCs fight germs.

Exam Tip: Red blood cells contain haemoglobin, which binds with oxygen molecules.

Question 2. Pulse rate indicate the rate of heart beat.
Answer: True
In simple words: Each pulse beat in your wrist corresponds directly to one heartbeat.

Exam Tip: You can feel your pulse by placing fingers over the radial artery in your wrist.

Question 3. Pure blood is circulated through the left part of heart.
Answer: True
In simple words: The left atrium and left ventricle handle oxygenated blood coming from the lungs.

Exam Tip: The septum keeps this pure blood separated from right-side deoxygenated blood.

Question 4. Xylem helps in the transport of food in plants.
Answer: False
In simple words: Xylem moves water and minerals upward; phloem transports prepared food.

Exam Tip: Xylem transport is unidirectional (upward only), whereas phloem transport is bidirectional.

Question 5. Hydra and sponges posses blood circulatory system.
Answer: False
In simple words: Sponges and Hydra use circulating surrounding water instead of blood.

Exam Tip: Water brings in food and oxygen and flushes away waste in simple aquatic animals.

Question 6. Human urine consists of 95% water, 2.5% urea and 2.5% other waste products.
Answer: True
In simple words: Normal urine is almost entirely water, carrying dissolved urea and waste salts.

Exam Tip: Urea is the primary nitrogenous waste product in human urine.

Define and Distinguish

Question. DEFINE : 1. Excretion
Answer: Excretion is the biological process of removing harmful and toxic metabolic waste products from the cells of living organisms.
In simple words: Excretion is the body's method of filtering and removing chemical wastes.

Exam Tip: Kidneys, lungs, and skin are the major human excretory organs.

Question. DISTINGUISH : 1. Arteries and veins
Answer: Arteries carry oxygen-rich blood away from the heart at high pressure; they have thick elastic walls and lack valves. Veins return deoxygenated blood back to the heart under low pressure; they have thinner walls and contain valves to prevent backflow.
In simple words: Arteries pump blood away from the heart with thick walls; veins bring blood back with one-way valves.

Exam Tip: Remember pulmonary vessels as the exceptions: pulmonary artery carries deoxygenated blood, pulmonary vein carries oxygenated blood.

Question. DISTINGUISH : 2. Xylem and Phloem
Answer: Xylem transports water and dissolved minerals upward from roots to leaves and consists mostly of dead cells. Phloem distributes prepared glucose and food from green leaves to all growing parts of the plant and consists of living cells.
In simple words: Xylem carries water up from the soil; phloem carries food everywhere from leaves.

Exam Tip: Xylem transport relies on physical suction pull; phloem transport requires biological energy.

Diagrams

Question 1. Schematic human blood circulatory system .(fig:11.3)
Answer: The human circulatory system features double circulation: the right side pumps blood through the pulmonary loop to the lungs, while the left side pumps blood through the systemic loop to the rest of the body.

In simple words: Blood loops through the lungs to get oxygen and then through the body to deliver it.

Exam Tip: Label the heart, lungs, body organs, pulmonary loop, and systemic loop.

Question 2. Human excretory system . (fig:11.6)
Answer: The human urinary system consists of a pair of bean-shaped kidneys that filter blood, two thin ureters that transport urine, an expandable urinary bladder that stores urine, and a urethra that expels it.

In simple words: Kidneys filter urine down two tubes into a storage bladder that empties through the urethra.

Exam Tip: Be sure to label both kidneys, the ureters, the urinary bladder, and the urethra.

CH. 12 : REPRODUCTION IN PLANTS

I. Fill in the Blanks

Question 1. Male reproductive part of a plant is __________________.
Answer: stamen
In simple words: The stamen is the male part of a flower that produces pollen grains.

Exam Tip: A stamen consists of a slender filament topped with a pollen-producing anther.

Question 2. Plants produce seeds as a result of _______________ reproduction.
Answer: sexual
In simple words: Seeds develop when male pollen fertilizes a female flower ovule.

Exam Tip: Asexual reproduction does not produce seeds.

Question 3. Asexual reproduction in spirogyra is ________________.
Answer: fragmentation
In simple words: Green pond spirogyra breaks into smaller pieces that grow into new filaments.

Exam Tip: Algae multiply rapidly in water bodies through fragmentation.

Question 4. Mustard and Rose have _____________ flowers.
Answer: bisexual
In simple words: Mustard and rose blossoms contain both male stamens and female pistils in the same flower.

Exam Tip: Flowers containing both reproductive organs are termed bisexual or complete flowers.

Question 5. The seeds develop from the _________________.
Answer: ovules
In simple words: Fertilized flower ovules grow into protective seeds.

Exam Tip: Ovules develop into seeds, while the surrounding ovary ripens into the fruit.

Question 6. Production of new individuals from vegetative parts of a plant is called _________________.
Answer: vegetative propagation
In simple words: Growing new plants from stems, roots, or leaves is called vegetative propagation.

Exam Tip: Potato eyes, ginger rhizomes, and Bryophyllum leaves reproduce by vegetative propagation.

II Write True or False

Question 1. Yeast is a single celled organism.
Answer: True
In simple words: Yeast is a microscopic, single-celled fungus that reproduces by budding.

Exam Tip: In budding, a tiny bulb-like projection called a bud grows out from the parent yeast cell.

Question 2. The zygote develops into an embryo.
Answer: True
In simple words: The single fertilized cell multiplies to form an embryo inside the seed.

Exam Tip: The plant embryo inside a seed sprouts into a seedling under favorable conditions.

Question 3. The production of new individuals from their parents is known as respiration.
Answer: False
In simple words: Making offspring is called reproduction, not respiration.

Exam Tip: Reproduction ensures the continuity of a species generation after generation.

Question 4. Pistil is the female reproductive part of a plant.
Answer: True
In simple words: The pistil in the center of a flower is its female organ.

Exam Tip: A pistil consists of the stigma, style, and ovary.

Question 5. Corn and Papaya produce bisexual flowers.
Answer: False
In simple words: Corn and papaya bear unisexual flowers with either only stamens or only pistils.

Exam Tip: Unisexual flowers have only one type of reproductive organ.

Question 6. Plants produce seeds as a result of asexual reproduction.
Answer: False
In simple words: Seeds only form through sexual reproduction involving pollination and fertilization.

Exam Tip: Asexual reproduction produces new plants without seeds.

Question 7. The fruit is a ripened ovary.
Answer: True
In simple words: After fertilization, the flower's ovary swells and ripens into a tasty fruit.

Exam Tip: The ovary wall becomes the fruit wall (pericarp).

Question 8. In asexual reproduction, only one parent is involved.
Answer: True
In simple words: A single parent organism creates offspring in asexual reproduction.

Exam Tip: The offspring are exact genetic clones of the single parent.

III Name the Following

Question 1. Two types of pollination seen in flowers.
Answer: Self-pollination and cross-pollination
In simple words: Pollen can land on the same flower (self) or travel to another flower (cross).

Exam Tip: Wind, water, and insects are common agents of cross-pollination.

Question 2. Two seeds dispersed by animals.
Answer: Xanthium and Urena
In simple words: Xanthium and Urena seeds have hooked spines that cling to animal fur.

Exam Tip: Hooked appendages allow these seeds to hitchhike onto animal bodies.

Question 3. Asexual reproduction in yeast.
Answer: Budding
In simple words: Yeast grows a small outward bump that pinches off as a new cell.

Exam Tip: Sometimes a chain of buds forms before they separate.

Question 4. Two spore producing plants.
Answer: Moss and fern
In simple words: Mosses and ferns reproduce by releasing light, microscopic spores.

Exam Tip: Spores have hard protective coats to survive dry conditions.

Question 5. Two winged seeds
Answer: Drumstick and maple
In simple words: Drumstick and maple seeds have thin wings that help wind carry them far away.

Exam Tip: Winged seeds are lightweight and spin like propellers in the breeze.

IV Define and V Distinguish

Question. Define: 1. Pollination
Answer: Pollination is the transfer of pollen grains from the anther of a flower to the receptive stigma of the same or another flower.
In simple words: Pollination is moving pollen powder from the male anther to the female stigma.

Exam Tip: Bees and butterflies are crucial insect pollinators for crops.

Question. Define: 2. Fertilisation
Answer: Fertilisation is the fusion of a male gamete with a female gamete inside the ovule to produce a single-celled zygote.
In simple words: Fertilization is the joining of male and female cells to begin a new seed.

Exam Tip: Fertilization takes place only after successful pollination.

Question. Define: 3. Reproduction
Answer: Reproduction is the fundamental biological process by which existing parent organisms produce new individuals of their own species.
In simple words: Reproduction is how living things make babies to continue their kind.

Exam Tip: Organisms reproduce either sexually or asexually.

Question. Distinguish: Unisexual and bisexual flowers.
Answer: Unisexual flowers contain either only male stamens or only female pistils (e.g., corn, papaya, cucumber). Bisexual flowers possess both stamens and pistils together within the same flower (e.g., mustard, rose, petunia).
In simple words: Unisexual flowers have only male or only female parts, while bisexual flowers have both in one bloom.

Exam Tip: Provide at least one correct plant example for each flower type.

LN. 13 : MOTION AND TIME

I Fill in the Blanks

Question 1. The distance moved by an object in a unit time is called its ___________.
Answer: speed
In simple words: Speed tells us how much distance an object covers in a set amount of time.

Exam Tip: Formula: \( \text{Speed} = \frac{\text{Distance}}{\text{Time}} \).

Question 2. Basic unit of measuring speed is _____________.
Answer: metre per second (m/s)
In simple words: The standard unit for speed is meters travelled in one second.

Exam Tip: Vehicle speeds are commonly written in kilometers per hour (km/h).

Question 3. ______________ events are used for the measurement of time.
Answer: Periodic
In simple words: Natural events that repeat at fixed intervals, like sunrises, help us measure time.

Exam Tip: Pendulum swings are classic examples of periodic motion.

Question 4. A _______________ consists of a small metallic ball or a piece of stone suspended from a rigid stand by a thread.
Answer: simple pendulum
In simple words: A simple pendulum is a weight swinging back and forth on a hanging string.

Exam Tip: Galileo was the first scientist to investigate pendulum motion.

Question 5. The metallic ball is called the ______________ of the pendulum.
Answer: bob
In simple words: The heavy hanging metal ball of a pendulum is called its bob.

Exam Tip: The bob swings back and forth around its resting central position.

Question 6. The to and fro motion of a simple pendulum is an example of a ____________ or an ______________ motion.
Answer: periodic, oscillatory
In simple words: A swinging pendulum shows regular back-and-forth oscillatory motion.

Exam Tip: Both words - periodic and oscillatory - describe this regular swinging.

Question 7. Meter that measures the distance moved by the vehicle is known as ____________________.
Answer: odometer
In simple words: An odometer is the dashboard meter that counts total kilometers driven.

Exam Tip: Do not confuse the odometer (measures distance) with the speedometer (measures speed).

Question 8. Motion of objects can be presented in pictorial from by their __________.
Answer: distance-time graphs
In simple words: A distance-time graph draws a picture showing how far something travels over time.

Exam Tip: A straight diagonal line on a distance-time graph represents uniform speed.

Question 9. Rockets, launching satellites into earth’s orbit often attain speeds up to ___________________ Km/s.
Answer: 8
In simple words: Space rockets reach enormous speeds of roughly 8 kilometers every second.

Exam Tip: In contrast, a garden snail crawls at a speed of only about 0.01 m/s.

Question 10. The basic unit of time is ________________.
Answer: second (s)
In simple words: The standard scientific unit of time is the second.

Exam Tip: Larger everyday units of time are minutes and hours.

II. Write True or False

Question 1. A year was fixed as the time taken by the earth to complete one revolution of the sun.
Answer: True
In simple words: One year equals the time Earth takes to orbit once around the sun.

Exam Tip: Earth completes one full orbit in approximately 365.25 days.

Question 2. A nanosecond is one billionth of a second.
Answer: True
In simple words: A nanosecond is an ultra-fast fraction: 1 divided by one billion seconds.

Exam Tip: Modern computer chips perform operations measured in nanoseconds.

Question 3. The motion of a pendulum is an example of non-periodic motion.
Answer: False
In simple words: A pendulum repeats swings at exact time intervals, so its motion is periodic.

Exam Tip: The constant time taken per swing is what makes pendulum clocks work.

Question 4. In ancient time people used to measure time with help of clock or wristwatch.
Answer: False
In simple words: Ancient civilizations relied on sundials, sand hourglasses, and water clocks.

Exam Tip: Modern quartz wristwatches were invented only in the twentieth century.

Question 5. The time taken by the pendulum to complete one oscillation is called its time period.
Answer: True
In simple words: The time required for one full swing cycle is called the time period.

Exam Tip: The time period depends on string length, not on the mass of the bob.

Question 6. The graph for non-uniform motion is a curve line.
Answer: True
In simple words: Changing speed shows up as a bent or curved line on a distance-time graph.

Exam Tip: A straight sloping line means steady (uniform) speed; a curved line means changing speed.

III Name the Following

Question 1. Name any two ancient – time measuring devices.
Answer: Sundial and sand clock (hourglass)
In simple words: Ancient people tracked hours using sun shadows and falling sand.

Exam Tip: Water clocks were also widely used in ancient times.

Question 2. Name the scientist who discovered pendulum.
Answer: Galileo Galilei
In simple words: Italian scientist Galileo discovered that a pendulum takes fixed time per swing.

Exam Tip: He observed a swinging chandelier inside a church in Pisa.

Question 3. Name the meter in vehicles which records the speed directly in Km/h.
Answer: Speedometer
In simple words: A speedometer displays the vehicle's driving speed in kilometers per hour.

Exam Tip: The speedometer indicates instantaneous speed at that precise moment.

Question 4. Name the ancient clock located at Jantar Mantar, Delhi.
Answer: Samrat Yantra (Giant sundial)
In simple words: The massive stone sundial at Jantar Mantar is named the Samrat Yantra.

Exam Tip: It was constructed by Maharaja Jai Singh II of Jaipur.

IV Define and V Distinguish

Question 1. Motion
Answer: Motion is the change in the position of an object relative to its surroundings with the passage of time.
In simple words: Motion means moving from one place to another over time.

Exam Tip: Motion can be rectilinear (straight), circular, or periodic.

Question 2. Speed
Answer: Speed is the total distance covered by a moving body divided by the total time taken to cover that distance.
In simple words: Speed is how fast an object covers ground.

Exam Tip: Always state the formula: \( \text{Speed} = \frac{\text{Total distance covered}}{\text{Total time taken}} \).

Question 3. Oscillation
Answer: An oscillation is one complete to-and-fro movement of a swinging object from one extreme position to the other and back.
In simple words: One full swing back and forth is called one oscillation.

Exam Tip: Moving from position A to B and returning to A counts as one full oscillation.

Question 1. Uniform motion and Non-uniform motion.
Answer: An object is in uniform motion if it travels equal distances in equal intervals of time along a straight line at constant speed. An object is in non-uniform motion if its speed varies, covering unequal distances in equal time intervals.
In simple words: Uniform motion means moving at steady speed, while non-uniform motion means speeding up or slowing down.

Exam Tip: A car driving through city traffic is a practical example of non-uniform motion.

CH. 14 : ELECTRIC CURRENT AND ITS EFFECTS

I Fill in the Blanks

Question 1. A thin wire in the bulb that glows when an electric current passes through it is called the ____________________.
Answer: filament
In simple words: The tiny tungsten wire inside a lightbulb that glows white-hot is its filament.

Exam Tip: Filaments are made of tungsten because it has an extremely high melting point.

Question 2. When the bulb gets _______________, its filament is broken.
Answer: fused
In simple words: A bulb is fused when its delicate filament snaps and stops current.

Exam Tip: A broken filament creates an open, incomplete electrical circuit.

Question 3. The coil of wire in an electric heater is known as ________________.
Answer: heating element
In simple words: The glowing wire loop inside a room heater is called its heating element.

Exam Tip: Heating elements are usually made of nichrome alloy wire.

Question 4. The amount of heat produced in a wire depends on its, ______________, ________________ and __________________.
Answer: material, length, thickness
In simple words: Heat generated in a wire depends on what metal it is, how long it is, and how thick it is.

Exam Tip: Remember: Material, Length, and Thickness (gauge) dictate heating resistance.

Question 5. When an electric current flows through a wire, it behaves like a _________________.
Answer: magnet
In simple words: Flowing electricity turns an insulated wire coil into a temporary magnet.

Exam Tip: This magnetic effect deflects a nearby compass needle.

Question 6. The ___________of an electric bell acts as an electromagnet in its working.
Answer: coil (electromagnet)
In simple words: The wire wound around iron pieces in a doorbell works as an electromagnet.

Exam Tip: Current powers the coil, pulling an iron armature that strikes the gong.

II State whether the following statements are True or False

Question 1. When the electric current is switched off, the coil generally loses its magnetism.
Answer: True
In simple words: Turning off the current instantly shuts off an electromagnet.

Exam Tip: This temporary magnetic property makes electromagnets very useful in cranes and bells.

Question 2. The wires used for making electric circuits do not normally become hot.
Answer: True
In simple words: Copper connecting wires have low resistance, so they stay cool.

Exam Tip: Good conductors allow current to flow without excessive heat buildup.

Question 3. The filament of an electric bulb never gets heated.
Answer: False
In simple words: The filament gets extremely hot so that it glows bright and gives off light.

Exam Tip: Bulb filaments heat up to over 2500 °C to emit white light.

Question 4. In a battery, the electric cells are always placed one after the other.
Answer: False
In simple words: Cells can be placed side by side as long as positive terminals connect to negative ones.

Exam Tip: Metal strips inside battery compartments connect side-by-side cells in series.

Question 5. Connecting many devices in a single socket does not affect the flow of current in a circuit.
Answer: False
In simple words: Plugging too many appliances into one socket overloads the circuit and can start fires.

Exam Tip: Overloading draws excessive current through the house wiring.

Question 6. Wear and tear of insulated wires can cause short circuits.
Answer: True
In simple words: When plastic insulation rubs off, bare live wires touch directly, causing a short circuit.

Exam Tip: Short circuits produce dangerous current surges and sparks.

Question 7. CFLs consume more electricity than ordinary bulbs.
Answer: False
In simple words: Energy-saving CFL bulbs use far less electricity than traditional filament bulbs.

Exam Tip: CFLs waste very little energy as heat compared to incandescent bulbs.

III Name the Following and IV Define

Question 1. The name of the scientist who first noticed the magnetic effect of current.
Answer: Hans Christian Oersted
In simple words: Oersted noticed a compass needle twitch whenever electric current flowed nearby.

Exam Tip: He made this foundational discovery in 1820.

Question 2. The switches being used in place of fuses.
Answer: Miniature Circuit Breakers (MCBs)
In simple words: MCBs are automatic safety switches that trip off when current spikes dangerously.

Exam Tip: Unlike fuses, MCBs do not need wire replacement; you simply flip them back on.

Question 3. A diagram made using symbols of electric components.
Answer: Circuit diagram
In simple words: A circuit diagram uses standard symbols to draw an electrical circuit clearly.

Exam Tip: Learn standard symbols for a cell, battery, bulb, switch, and resistor.

Question 4. The mark of safety necessary on electrical appliances.
Answer: ISI mark
In simple words: The ISI mark proves an electrical product meets official safety standards in India.

Exam Tip: The Bureau of Indian Standards (BIS) issues the ISI quality mark.

Question 1. Battery
Answer: A battery is a combination of two or more electric cells connected such that the positive terminal of one connects to the negative terminal of the next.
In simple words: A battery is a team of cells joined together to provide stronger electric current.

Exam Tip: Always draw the long line for positive (+) and the short, thick line for negative (-).

Question 2. Electromagnet
Answer: An electromagnet is a temporary magnet made by wrapping a coil of insulated wire around a soft iron core, which acts as a magnet only while current flows.
In simple words: An electromagnet is a wire coil that becomes magnetic whenever electricity is switched on.

Exam Tip: Electromagnets are used in electric bells, scrap-lifting cranes, and audio speakers.

Question 3. Fuse
Answer: A fuse is an electrical safety device containing a thin wire with a low melting point that melts and breaks the circuit during an unsafe current surge.
In simple words: A fuse is a safety wire that melts to protect appliances from power surges.

Exam Tip: Fuses prevent electrical fires by stopping overloaded currents immediately.

LN. 15 : LIGHT

I. Fill in the Blanks

Question 1. The change in the direction of light by a mirror is called ______________.
Answer: reflection of light
In simple words: When light rays bounce off a shiny mirror, it is called reflection.

Exam Tip: Smooth, shiny surfaces reflect light predictably at equal angles.

Question 2. The image formed by a ____________ lens is always virtual, erect and smaller in size.
Answer: concave
In simple words: A concave lens always makes things look upright, smaller, and virtual.

Exam Tip: Concave lenses spread light rays outward (diverging lens).

Question 3. White light is composed of ______________ colours.
Answer: seven
In simple words: Normal white sunlight is a mix of seven rainbow colors (VIBGYOR).

Exam Tip: Passing white light through a glass prism splits it into these seven colors.

Question 4. The image of an object formed by a _____________ cannot be obtained on a screen.
Answer: plane mirror (or virtual image)
In simple words: Virtual images formed by bathroom mirrors cannot be projected onto a paper screen.

Exam Tip: Only real images can be caught on a screen.

Question 5. _____________ are used by dentists to see an enlarged image of the teeth.
Answer: Concave mirrors
In simple words: Dentists use concave mirrors up close to see tooth cavities magnified.

Exam Tip: Concave mirrors produce an upright, enlarged virtual image when held close to an object.

II Name the Following and III True or False

Question 1. An image that can be obtained on the screen -
Answer: Real image
In simple words: A real image can be projected onto a physical screen, like a movie in a cinema.

Exam Tip: Real images are always inverted (upside down).

Question 2. The lens which feel thinner in the middle than at the edges -
Answer: Concave lens
In simple words: A concave lens caves inward, making it thin in the center and thick on the rims.

Exam Tip: Concave lenses diverge light rays outward.

Question 3. The lens known as magnifying glass -
Answer: Convex lens
In simple words: A convex lens bulges in the middle and acts as a handheld reading glass.

Exam Tip: Convex lenses converge light rays inward to a focal point.

Question 4. The lens known as diverging lens -
Answer: Concave lens
In simple words: A concave lens spreads light rays apart, so it is called a diverging lens.

Exam Tip: Convex lenses converge light, while concave lenses diverge light.

Question 5. The mirror which can form both real as well as virtual images.
Answer: Concave mirror
In simple words: A curved concave mirror makes inverted real pictures far away and magnified virtual pictures up close.

Exam Tip: Plane and convex mirrors can only create virtual images.

Question 6. The large arc of seven colours VIBGYOR in the sky.
Answer: Rainbow
In simple words: A rainbow is a seven-color sky arch made when raindrops split sunlight.

Exam Tip: VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange, Red.

Question 1. The image formed by a plane mirror is inverted -
Answer: False
In simple words: A plane mirror creates an erect (upright) image with left-right lateral reversal.

Exam Tip: The image is laterally inverted (left appears right), but not vertically inverted.

Question 2. A convex lens is thicker in the middle than at the edges -
Answer: True
In simple words: A convex lens bulges out thick in the center and tapers at the borders.

Exam Tip: This bulging center brings incoming parallel rays to a focus.

Question 3. A concave mirror always forms real image -
Answer: False
In simple words: Holding an object very close to a concave mirror creates an upright virtual image.

Exam Tip: It produces a virtual, erect, magnified image when an object is placed between the pole and focus.

Question 4. Any polished or shining surface can act as mirror -
Answer: True
In simple words: Shiny metal spoons and still water surfaces reflect light just like mirrors.

Exam Tip: Regular reflection occurs whenever light hits any highly smooth surface.

IV Define and V Distinguish

Question. Reflection of light
Answer: Reflection of light is the phenomenon where light rays strike a polished or shiny surface and bounce back into the same medium.
In simple words: Reflection is light bouncing off a shiny surface like a rubber ball off a wall.

Exam Tip: Mirrors change the direction of light according to the laws of reflection.

Question. Real image & Virtual image
Answer: A real image is formed where light rays actually meet; it can be captured on a screen and is always inverted (e.g., cinema projector image). A virtual image is formed where light rays only appear to diverge; it cannot be projected on a screen and is always erect (e.g., face in a plane mirror).
In simple words: Real images can be caught on a screen upside down; virtual images cannot be caught on a screen and stay upright.

Exam Tip: The ability to be formed on a screen is the definitive test separating real images from virtual ones.

CH. 16 : WATER : A PRECIOUS RESOURSE

I Fill in the Blanks

Question 1. The ________________ in the soil indicates the presence of underground water.
Answer: moisture
In simple words: Damp soil particles signal that water is stored underground nearby.

Exam Tip: Digging into moist soil eventually leads to the water table.

Question 2. Water in the aquifers can be usually pumped out with help of __________ or _______________.
Answer: tube wells, hand pumps
In simple words: Deep ground water in aquifers is pumped up using hand pumps and electric tube wells.

Exam Tip: Aquifers are water-bearing rock layers lying below the water table.

Question 3. _____________ was the traditional way of collecting water.
Answer: Bawri (Stepwell)
In simple words: Bawris were traditional stepwells built in India to collect and store rainwater.

Exam Tip: Reviving ancient stepwells helps restore local groundwater supplies.

Question 4. Shortage of ___________ has become a matter of concern.
Answer: freshwater
In simple words: Scarcity of clean drinking water has become a major global challenge.

Exam Tip: Less than 1% of all water on Earth is readily available for human use.

II Write True or False

Question 1. Celebration of water day is to attract the attention of everybody towards the importance of conserving water.
Answer: True
In simple words: World Water Day reminds communities to save and value every drop of water.

Exam Tip: World Water Day is celebrated globally on March 22 every year.

Question 2. 76% of the earth’s surface is covered with water.
Answer: False
In simple words: About 71% of Earth's surface is covered by oceans, lakes, and rivers.

Exam Tip: Remember: Roughly 71% of Earth's surface is water, mostly saline sea water.

Question 3. Glaciers are the solid form of water.
Answer: True
In simple words: Mountain glaciers and polar ice caps hold water in solid ice form.

Exam Tip: Water exists in three natural states: ice (solid), liquid water, and water vapor (gas).

Question 4. Excessive rains cause droughts whereas the absence of rains results in floods.
Answer: False
In simple words: Heavy rains cause floods, while lack of rain leads to droughts.

Exam Tip: Floods submerge land, while droughts dry up crops and ground water.

III Define and IV Diagram

Question 1. Drip irrigation.
Answer: Drip irrigation is an economical watering method that uses narrow tubing to trickle water drop by drop directly onto plant roots, preventing water wastage.
In simple words: Drip irrigation delivers water directly to plant roots one drop at a time to save water.

Exam Tip: Drip irrigation minimizes evaporation loss and is ideal for water-scarce farmlands.

Question. Ground water and Water table.
Answer: The water table is the upper boundary of the underground zone saturated with water. Rainwater seeps down through soil pores (infiltration) and collects above impermeable rock layers to form groundwater.

In simple words: The water table is the top surface of the underground pool of groundwater.

Exam Tip: Clearly label the soil layer, the dashed water table line, the groundwater zone, and the bedrock.

CH. 18 : WASTE WATER STORY

I. Fill in the Blanks

Question 1. Waste water is treated in a ________________.
Answer: wastewater treatment plant (WWTP)
In simple words: Dirty drain water is cleaned inside a wastewater treatment plant.

Exam Tip: WWTPs remove physical, chemical, and biological pollutants before discharging water.

Question 2. The sludge is decomposed by ____________ bacteria.
Answer: anaerobic
In simple words: Anaerobic bacteria digest settled organic sludge in closed tanks without air.

Exam Tip: This digestion produces biogas that can be used as clean fuel.

Question 3. _____________ and contaminated drinking water is the cause of a large number of diseases.
Answer: Poor sanitation
In simple words: Dirty surroundings and contaminated drinking water cause many dangerous infections.

Exam Tip: Open defecation pollutes surface water bodies and groundwater wells.

Question 4. The process of waste water treatment is known as _______________.
Answer: sewage treatment
In simple words: Cleaning liquid sewage so it can be reused safely is called sewage treatment.

Exam Tip: It involves physical screening, biological aeration, and chemical disinfection.

Question 5. Sewage is a _____________________ waste.
Answer: liquid
In simple words: Sewage is dirty liquid waste flushed from homes, businesses, and hospitals.

Exam Tip: Most of sewage is water carrying dissolved and suspended contaminants.

Question 6. The activated sludge is about _____________ % water.
Answer: 97
In simple words: Activated sludge is roughly 97 percent water and must be dried before use as manure.

Exam Tip: Sand drying beds or centrifuges remove water from activated sludge.

Question 7. The suspended impurities dissolved in swage are called ______________.
Answer: contaminants
In simple words: Organic and inorganic pollutants in wastewater are called contaminants.

Exam Tip: Contaminants include disease-causing microbes, plant nutrients, and toxic chemicals.

II Name the Following and III True or False

Question 1. The nutrient present in sewage.
Answer: Nitrogen and phosphorus
In simple words: Sewage carries plant nutrients like nitrogen and phosphorus from fertilizers and soaps.

Exam Tip: Excessive nutrients dumped into lakes trigger harmful algal blooms.

Question 2. By products of waste water treatment.
Answer: Biogas and dried sludge
In simple words: Sewage plants produce useful biogas fuel and nutrient-rich soil manure.

Exam Tip: Sludge is used as soil fertilizer, and biogas generates electricity.

Question 3. A plant which can absorb waste water rapidly and release pure water vapour to the atmosphere.
Answer: Eucalyptus tree
In simple words: Eucalyptus trees drink up wastewater quickly and transpire clean water vapor into the air.

Exam Tip: Planting eucalyptus along sewage ponds is a natural wastewater disposal technique.

Question 4. Solid waste extracted in sewage treatment.
Answer: Sludge
In simple words: Heavy organic solids that settle to the bottom of clarifier tanks form sludge.

Exam Tip: Sludge is scraped out from the bottom of primary sedimentation tanks.

Question 5. Any two water borne disease.
Answer: Cholera and typhoid
In simple words: Drinking sewage-polluted water can cause cholera and typhoid fever.

Exam Tip: Dysentery, jaundice, and polio are also waterborne diseases.

Question 6. Expand WWTP.
Answer: Waste Water Treatment Plant
In simple words: WWTP stands for Waste Water Treatment Plant.

Exam Tip: Write all four words accurately without spelling errors.

Question 1. Urea is an inorganic impurity present in sewage.
Answer: False
In simple words: Urea is an organic impurity produced from human metabolic waste.

Exam Tip: Phosphates, nitrates, and metals are inorganic impurities; urea is organic.

Question 2. Sewerage is a transport system that carries sewage to the treatment plant.
Answer: True
In simple words: Sewerage is the network of underground pipes that carries dirty water to the treatment station.

Exam Tip: A sewer is a single pipe, while sewerage refers to the whole network.

Question 3. Chemical toilet is a low cost onsite sewage disposal system.
Answer: True
In simple words: Chemical toilets treat human waste directly on site without connecting to sewer pipes.

Exam Tip: Composting toilets and septic tanks are other examples of onsite systems.

Question 4. Sewage is solid waste which causes water and soil pollution.
Answer: False
In simple words: Sewage is liquid waste carrying dissolved and suspended contaminants.

Exam Tip: Sewage is primarily wastewater containing only a small percentage of solid particles.

Question 5. Untreated human excreta is a health hazard.
Answer: True
In simple words: Open human waste contaminates drinking sources and spreads epidemics.

Exam Tip: It pollutes both ground and surface water, causing outbreaks of waterborne diseases.