ICSE Class 6 Physics Sample Paper with Solutions Set 05

Question 1
Choose the correct answer out of the four available choices given under each question. [15]

1. What is the work done in lifting a 5 kg body through a height of 10 m? (\( g = 10\text{ m/s}^2 \)) [1 Mark]
(a) 5 J
(b) 15 J
(c) 50 J
(d) 500 J

Answer: (d) 500 J

\( W = m \times g \times h = 5 \times 10 \times 10 = 500\text{ J} \).

Teacher's Note:
a) Work done against gravity is calculated using the formula \( W = mgh \), where \( m \) is mass, \( g \) is acceleration due to gravity, and \( h \) is height.
b) Ensure all quantities are in SI units before substituting into the formula.

2. If the velocity of a moving car is reduced to half its original velocity, its kinetic energy would [1 Mark]
(a) Become four times
(b) Become two times
(c) Become one fourth
(d) Become half

Answer: (c) Become one fourth

Kinetic energy is directly proportional to the square of the velocity (\( \text{K.E.} = \frac{1}{2}mv^2 \)). When velocity becomes \( v/2 \), the new kinetic energy becomes \( \frac{1}{2}m(v/2)^2 = \frac{1}{4}(\frac{1}{2}mv^2) \).

Teacher's Note:
a) Remember that kinetic energy has a quadratic dependence on speed, so halving the speed reduces energy by a factor of four.
b) Students often mistakenly think kinetic energy changes linearly with velocity.

3. The S.I. unit of length is [1 Mark]
(a) Metre
(b) Yard
(c) Cubit
(d) Foot

Answer: (a) Metre

The standard International System of Units (SI) base unit for measuring length is the metre.

Teacher's Note:
a) Yard, cubit, and foot are traditional or imperial units of measurement, not standard SI units.
b) Memorize the standard SI units for fundamental physical quantities.

4. When a bar magnet is suspended freely, it comes to rest in the [1 Mark]
(a) East-West direction
(b) North-East direction
(c) North-South direction
(d) South-West direction

Answer: (c) North-South direction

A freely suspended bar magnet always aligns itself along the geographical north-south direction due to Earth's magnetic field.

Teacher's Note:
a) This is a fundamental property of magnets used historically for navigation in magnetic compasses.
b) Be precise with geographical orientation terms.

5. Which type/types of levers always have mechanical advantage greater than 1? [1 Mark]
(a) Class I
(b) Class II
(c) Class III
(d) All of the above

Answer: (b) Class II

In Class II levers, the load is between the fulcrum and the effort, meaning the effort arm is always longer than the load arm, resulting in a mechanical advantage greater than 1.

Teacher's Note:
a) Mechanical advantage is the ratio of the effort arm to the load arm.
b) Class III levers always have a mechanical advantage less than 1, while Class I can have a mechanical advantage greater than, equal to, or less than 1.

6. The unit of 1 atm is taken as the unit of [1 Mark]
(a) Force
(b) Area
(c) Work
(d) Pressure

Answer: (d) Pressure

One atmosphere (atm) is a standard unit of atmospheric pressure.

Teacher's Note:
a) 1 atm is approximately equal to \( 1.013 \times 10^5\text{ Pa} \).
b) Do not confuse pressure units with force (Newton) or work (Joule).

7. Which of the following is force at a distance? [1 Mark]
(a) Muscular force
(b) Magnetic force
(c) Friction force
(d) Normal reaction force

Answer: (b) Magnetic force

Magnetic force is a non-contact force that can act across a distance without physical touch.

Teacher's Note:
a) Forces like muscular, friction, and normal reaction require physical contact between objects.
b) Non-contact forces include magnetic, electrostatic, and gravitational forces.

8. Tyres are provided with deep grooves on their surface to [1 Mark]
(a) Increase the friction
(b) Reduce the cost of material used
(c) Decrease the friction
(d) Make them look attractive

Answer: (a) Increase the friction

Deep grooves improve grip and increase friction between the tyre and the road, preventing skidding.

Teacher's Note:
a) Friction is essential for vehicles to start, stop, and turn safely without slipping.
b) Worn-out tyres lack grooves, reducing friction and increasing the risk of accidents on wet roads.

9. For a wheelbarrow ____________ is at the centre. [1 Mark]
(a) Fulcrum
(b) Effort
(c) Load
(d) None of the above

Answer: (c) Load

A wheelbarrow is a Class II lever where the wheel acts as the fulcrum at one end, the handles are where effort is applied at the other end, and the load is placed in the middle.

Teacher's Note:
a) Class II levers always have the load situated between the fulcrum and the effort.
b) Identify the positions of fulcrum, load, and effort carefully for common tools.

10. A cubit is length equal to [1 Mark]
(a) The distance between nose and toe
(b) The distance between finger-tips and elbow
(c) 3 metres
(d) The distance between outstretched arm and chin.

Answer: (b) The distance between finger-tips and elbow

A cubit is an ancient non-standard unit of length based on the length of the forearm from the elbow to the tip of the middle finger.

Teacher's Note:
a) Non-standard units vary from person to person, which is why standard SI units were adopted.
b) Remember definitions of historical measurement units like cubit, fathom, and hand span.

11. Potential energy of a person is minimum when [1 Mark]
(a) A person is standing
(b) A person is sitting on a chair
(c) A person is sitting on the ground
(d) A person is lying on the ground

Answer: (d) A person is lying on the ground

Potential energy (\( PE = mgh \)) depends directly on height above the ground. Lying on the ground minimizes the center of mass height to nearly zero.

Teacher's Note:
a) Gravitational potential energy increases with height.
b) The lowest possible vertical position relative to the reference ground level yields the minimum potential energy.

12. Tools meant for cutting and piercing always have [1 Mark]
(a) Sharp edges
(b) Smooth edges
(c) Long handle
(d) All of the above

Answer: (a) Sharp edges

Sharp edges have a very small surface area, which concentrates the applied force to produce high pressure for effective cutting and piercing.

Teacher's Note:
a) Pressure is inversely proportional to surface area (\( P = F/A \)).
b) Smaller area means greater pressure for the same amount of applied force.

13. A force which can change the motion of an object without actually touching it is [1 Mark]
(a) Contact force
(b) Non contact force
(c) Distant force
(d) None of the above

Answer: (b) Non contact force

Forces that act across space without physical contact are known as non-contact forces.

Teacher's Note:
a) Gravitational, magnetic, and electrostatic forces are classic examples of non-contact forces.
b) Note that option (c) is a colloquial term, while the proper scientific classification is non-contact force.

14. Permanent magnets are made up of [1 Mark]
(a) Copper
(b) Soft iron
(c) Steel
(d) Aluminium

Answer: (c) Steel

Steel retains its magnetism for a long time once magnetized, making it suitable for permanent magnets, whereas soft iron is used for temporary electromagnets.

Teacher's Note:
a) Permanent magnets require high retentivity and coercivity, qualities found in steel and special alloys like Alnico.
b) Soft iron is easily magnetized and demagnetized, ideal for temporary magnets.

15. A force can do which of the following? [1 Mark]
(a) It can alter the speed of the moving object
(b) It can change the direction of the motion of the body
(c) It can change the shape of an object
(d) All of the above

Answer: (d) All of the above

A force can initiate motion, stop motion, speed up or slow down an object, change its direction of travel, or deform its shape.

Teacher's Note:
a) Force is a push or pull that produces multiple mechanical effects on bodies.
b) Always consider all listed physical effects of forces in multiple-choice questions.

Question 2

(A) Name the following. [5]

1. A quantity which does not depend on other quantities. [1 Mark]

Answer:
Fundamental quantity.

Teacher's Note:
a) Fundamental quantities form the base of physical measurement systems (e.g., mass, length, time).
b) Derived quantities depend on fundamental quantities.

2. Force exerted by a charged body. [1 Mark]

Answer:
Electrostatic force.

Teacher's Note:
a) Electrostatic force is a non-contact force acting between electric charges.
b) It can be either attractive or repulsive.

3. Unit of pressure. [1 Mark]

Answer:
Pascal (or N/m²).

Teacher's Note:
a) Named after the scientist Blaise Pascal.
b) One Pascal is equal to a force of one Newton acting over an area of one square metre.

4. Energy produced by vibrating objects. [1 Mark]

Answer:
Sound energy.

Teacher's Note:
a) Sound requires a material medium to propagate and originates from mechanical vibrations.
b) Distinguish sound energy from other forms like light or heat energy.

5. Space occupied by an object. [1 Mark]

Answer:
Volume.

Teacher's Note:
a) Volume is a derived geometric quantity measured in cubic units like m³ or cm³.
b) Not to be confused with mass or area.

(B) Fill in the blanks. [5]

1. __________ is the degree of hotness or coldness of a body. [1 Mark]

Answer:
Temperature.

Teacher's Note:
a) Temperature measures thermal state, whereas heat is thermal energy in transit.
b) Commonly measured in Celsius, Fahrenheit, or Kelvin.

2. __________ is the ultimate source of energy. [1 Mark]

Answer:
Sun.

Teacher's Note:
a) Almost all renewable and non-renewable energy sources on Earth originate from solar energy.
b) Photosynthesis, wind, and water cycles are driven by the Sun.

3. Unlike poles of two magnets __________ each other. [1 Mark]

Answer:
Attract.

Teacher's Note:
a) North and South poles attract, while like poles (North-North or South-South) repel.
b) This is the fundamental law of magnetism.

4. Nuclear energy is released in the form of __________ energy when an atom disintegrates. [1 Mark]

Answer:
Heat (or thermal / nuclear energy).

Teacher's Note:
a) Nuclear fission or radioactive decay converts mass into immense amounts of thermal energy.
b) This heat is typically harnessed to generate electricity in power plants.

5. __________ is applied to moving parts of a machine to reduce friction. [1 Mark]

Answer:
Lubricant (or oil / grease).

Teacher's Note:
a) Lubricants form a thin film between sliding surfaces, replacing solid friction with fluid friction.
b) This minimizes wear and tear and energy loss in machines.

Question 3

(A) Match the following. [5]

Answer:
1 - b (Note: Official key matches 1 to Metre, 2 to Class II lever, 3 to Electric to magnetic, 4 to Kelvin, 5 to Class III lever). Correct pairing:
1 - a (Length - Metre)
2 - b (Oar - Class II lever)
3 - c (Electromagnet - Electric to magnetic)
4 - d (Temperature - Kelvin)
5 - e (Forceps - Class III lever)

Teacher's Note:
a) Match physical quantities with their SI units and mechanical devices with their lever classes accurately.
b) Double-check all matching rows before finalizing answers in exams.

(B) Correct the following sentences. [5]

1. Friction resists motion because surfaces are attracted to each other. [1 Mark]

Answer:
Friction resists motion because surfaces are in contact with each other (due to microscopic irregularities interlocking).

Teacher's Note:
a) Friction arises due to irregularities and interlocking of microscopic roughness between contacting surfaces.
b) Molecular attraction plays a secondary role compared to mechanical interlocking.

2. A class III lever has fulcrum in the middle. [1 Mark]

Answer:
A class III lever has effort in the middle (between the fulcrum and the load).

Teacher's Note:
a) Class I has the fulcrum in the middle.
b) Class III levers prioritize speed and range of motion over mechanical advantage.

3. The SI unit of area is metre cubed. [1 Mark]

Answer:
The SI unit of area is metre squared (m²).

Teacher's Note:
a) Metre cubed (m³) is the SI unit of volume, not area.
b) Area is calculated as length multiplied by breadth.

4. Mercury is used in a thermometer because it wets the glass. [1 Mark]

Answer:
Mercury is used in a thermometer because it does not wet the glass.

Teacher's Note:
a) Mercury has a high cohesive force and does not stick to glass capillary walls, ensuring accurate readings.
b) It also has a uniform expansion rate and high boiling point.

5. The strength of an electromagnet can be increased by increasing the number of turns or decreasing the current flowing through the coil. [1 Mark]

Answer:
The strength of an electromagnet can be increased by increasing the number of turns or increasing the current flowing through the coil.

Teacher's Note:
a) Electromagnet strength is directly proportional to both current and the number of turns in the coil.
b) Decreasing current would weaken, not strengthen, the electromagnet.

Question 4

(A) Give examples to show that friction is both a friend and a foe. [5 Marks]

Answer:
Friction is called a necessary evil because it is indispensable for many daily activities while also causing unwanted energy loss and wear.
Examples of friction as a friend:
1. We are able to walk and run comfortably without slipping due to friction between our shoes and the ground.
2. Writing with a pen or pencil on paper is possible because of friction.
3. Nails and screws stay firmly fixed in walls due to frictional forces.
Examples of friction as a foe:
1. Wear and tear of machine parts and shoe soles is caused by continuous friction.
2. Friction generates unwanted heat in machinery, wasting energy and causing overheating.
3. Vehicles consume more fuel due to frictional resistance opposing motion.

Teacher's Note:
a) Clearly distinguish between beneficial applications of friction (walking, writing) and detrimental effects (wear, heat loss).
b) Use bullet points for clear presentation in descriptive answers.

(B) What are the five important uses of a magnet? [5 Marks]

Answer:
1. Magnets are used in magnetic compasses to find directions.
2. They are used in closure mechanisms of pencil boxes, refrigerator doors, and handbags.
3. Ceramic and powerful neodymium magnets are utilized in computer hard drives and electronic equipment.
4. They are used in generators, electric motors, and bicycle dynamos.
5. Magnets are incorporated into toys and scientific instruments to produce mechanical or levitation effects.

Teacher's Note:
a) Mention a mix of household, industrial, and scientific applications.
b) Keep each point concise and factually accurate.

Question 5

(A) Answer in one sentence: [5]

1. State the factors on which work done depends. [1 Mark]

Answer:
Work done depends on the magnitude of the applied force and the displacement of the body in the direction of the force.

Teacher's Note:
a) Expressed as \( W = F \times s \).
b) If there is no displacement, zero work is done regardless of how large the force is.

2. What is friction? [1 Mark]

Answer:
Friction is the opposing force that comes into play when one surface moves or tends to move over another surface.

Teacher's Note:
a) Friction always acts parallel to the contacting surfaces and opposite to the direction of motion.
b) It is caused by interlocking surface irregularities.

3. The base of taller buildings is made broader. Why? [1 Mark]

Answer:
The base of taller buildings is made broader to distribute the huge weight over a larger area, thereby reducing pressure and preventing sinking.

Teacher's Note:
a) Pressure is inversely proportional to area (\( P = F/A \)).
b) A larger base area decreases pressure on the foundation soil.

4. Name the two factors by which a machine's ability to do work is measured. [1 Mark]

Answer:
A machine's ability to do work is measured by its mechanical advantage and efficiency.

Teacher's Note:
a) Mechanical advantage compares output load to applied effort.
b) Efficiency measures the ratio of useful work output to total work input.

5. What are natural and artificial magnets? [1 Mark]

Answer:
Natural magnets are naturally occurring magnetic rocks like lodestone, whereas artificial magnets are man-made magnets created from iron, steel, or alloys.

Teacher's Note:
a) Natural magnets generally have irregular shapes and weak magnetic strength.
b) Artificial magnets can be shaped into bars, horseshoes, or needles and can have much stronger magnetic fields.

(B) Find the odd one out. [5]

1. Plastic, brass, iron, copper [1 Mark]

Answer:
Plastic.

Teacher's Note:
a) Iron, brass, and copper are metals, whereas plastic is a non-metal/polymer.
b) Alternatively, iron is magnetic while the others are non-magnetic metals, but classification by material type is standard.

2. Sharp knife, pointed heel, wide tyres, pointed nail [1 Mark]

Answer:
Wide tyres.

Teacher's Note:
a) Wide tyres are designed to increase surface area and reduce pressure, whereas knives, heels, and nails decrease area to increase pressure.
b) Core concept is pressure variation via surface area.

3. Sound energy, chemical energy, heat energy, light energy [1 Mark]

Answer:
Chemical energy.

Teacher's Note:
a) Chemical energy is potential/stored energy, whereas sound, heat, and light are forms of energy in active transit.
b) Understand stored versus transient forms of energy.

4. Wood, sun, water, wind [1 Mark]

Answer:
Wood.

Teacher's Note:
a) Wood is a conventional/biomass source, while sun, water, and wind are primary renewable natural sources (or non-conventional sources in classical context).
b) Check classification criteria carefully in energy source problems.

5. Nut cracker, sugar tongs, wheel barrow, bottle opener [1 Mark]

Answer:
Sugar tongs.

Teacher's Note:
a) Sugar tongs is a Class III lever, whereas nut crackers, wheelbarrows, and bottle openers are Class II levers.
b) Lever classification is based on the relative positions of fulcrum, load, and effort.

Question 6

(A) Show with the help of diagrams, the differences between I, II and III classes of levers. [5 Marks]

Answer:
Levers are categorized into three classes based on the relative positions of the fulcrum (F), load (L), and effort (E).
1. Class I Lever: The fulcrum is situated between the load and the effort (Load - Fulcrum - Effort order). Example: Beam balance, scissors. Mechanical advantage can be greater than, equal to, or less than 1.
2. Class II Lever: The load is situated between the fulcrum and the effort (Fulcrum - Load - Effort order). Example: Nutcracker, wheelbarrow. Mechanical advantage is always greater than 1.
3. Class III Lever: The effort is situated between the fulcrum and the load (Fulcrum - Effort - Load order). Example: Forceps, sugar tongs. Mechanical advantage is always less than 1.

[Figure: Three schematic lever diagrams showing (1) Class I with fulcrum in the middle between load and effort, (2) Class II with load in the middle between fulcrum and effort, and (3) Class III with effort in the middle between fulcrum and load.]

Teacher's Note:
a) Students must draw clear labeled diagrams showing F, L, and E positions for all three classes.
b) Memorize the mnemonic: FLE (1st class: F in middle; 2nd class: L in middle; 3rd class: E in middle).

(B) Define the following. [5]

1. One metre [1 Mark]

Answer:
One metre is defined as the distance between two fine lines engraved on a platinum-irridium bar kept at the International Bureau of Weights and Measures in Paris maintained at \( 0^{\circ}\text{C} \).

Teacher's Note:
a) This is the historical standard definition taught at the middle school level.
b) Modern definitions use the distance light travels in a vacuum, but stick to the standard textbook definition for exams.

2. Lower fixed point of thermometer [1 Mark]

Answer:
The lower fixed point of a thermometer is the temperature of melting pure ice, which is taken as \( 0^{\circ}\text{C} \).

Teacher's Note:
a) Also known as the ice point.
b) It serves as a reference calibration point on temperature scales.

3. Contact force [1 Mark]

Answer:
Contact forces are those forces that act only when objects are in physical contact with each other.

Teacher's Note:
a) Examples include muscular force, friction, and normal reaction.
b) Physical touch is mandatory for transmission of contact forces.

4. Potential energy [1 Mark]

Answer:
Potential energy is the energy possessed by a body by virtue of its position, state, or configuration with reference to the earth.

Teacher's Note:
a) Gravitational potential energy depends on mass, gravitational acceleration, and height (\( PE = mgh \)).
b) It is stored energy ready to be converted into kinetic energy.

5. Magnetic axis [1 Mark]

Answer:
The imaginary straight line joining the north and south poles of a magnet is called its magnetic axis.

Teacher's Note:
a) It passes through the interior of the magnet connecting both poles.
b) Essential concept in mapping magnetic field lines.

Question 7

(A) Answer the following.

1. What is an inclined plane? Give four examples of inclined planes commonly used in daily life? [2 Marks]

Answer:
An inclined plane is any sloping flat surface along which a load can be easily pushed or pulled to a higher level with less effort.
Four examples: Ramp, gangplank, winding staircase, and hill road.

Teacher's Note:
a) Inclined planes are simple machines that reduce the effort required to lift heavy loads vertically.
b) List distinct, recognizable everyday examples.

2. How is hydroelectricity produced? [3 Marks]

Answer:
1. River water is stored at a height in reservoirs behind dams.
2. When the stored water flows down through pipes, its potential energy converts into kinetic energy.
3. This fast-moving water rotates the blades of a turbine, which in turn drives a generator to convert mechanical energy into electrical energy (hydroelectricity).

Teacher's Note:
a) Trace the energy transformation chain: Potential Energy → Kinetic Energy → Mechanical Energy → Electrical Energy.
b) Emphasize the role of dams and turbines in energy conversion.

(B) Answer the following.

1. What is the use of [2 Marks]
i. Clinical thermometer
ii. Laboratory thermometer

Answer:
i. Clinical thermometer: Used for measuring human body temperature; its range is typically from \( 35^{\circ}\text{C} \) to \( 42^{\circ}\text{C} \) (or \( 94^{\circ}\text{F} \) to \( 108^{\circ}\text{F} \)).
ii. Laboratory thermometer: Used in laboratories for measuring temperatures of various substances and liquids; its range is typically from \( -10^{\circ}\text{C} \) to \( 110^{\circ}\text{C} \).

Teacher's Note:
a) Clinical thermometers feature a constriction (kink) to prevent mercury level from falling back before a reading is taken.
b) Laboratory thermometers lack this kink and have a wider measurement range.

2. State the important properties of a magnet. [3 Marks]

Answer:
1. A magnet attracts objects made of magnetic materials like iron, nickel, and steel.
2. When suspended freely by a thread, a magnet always comes to rest pointing in the geographic north-south direction.
3. The magnetic strength is concentrated at its two poles (North Pole and South Pole).
4. Magnetic poles always exist in pairs; magnetic monopoles do not exist.
5. Like poles repel each other, while unlike poles attract each other.

Teacher's Note:
a) List at least three to four key properties for full marks.
b) Highlight the non-existence of isolated magnetic poles as a fundamental law.