ICSE Class 6 Physics Sample Paper with Solutions Set 04

Question 1

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

1. Mechanical advantage (M.A), load (L) and effort (E) are related as [1 Mark]
(a) M.A = L \times E
(b) M.A \times E = L
(c) M.A \times L = E
(d) None of the above

Answer: (b) M.A \times E = L

Mechanical advantage is defined as the ratio of load to effort, expressed as \( \text{M.A} = \frac{L}{E} \), which gives \( \text{M.A} \times E = L \).

Teacher's Note:
a) Remember the fundamental principle of simple machines where Load equals Effort multiplied by Mechanical Advantage.
b) Students often confuse the relationship and write M.A equals L times E instead of dividing.

2. Which of the following is not a lever of class II? [1 Mark]
(a) Nail cutter
(b) Scissors
(c) A bottle opener
(d) Wheel barrow

Answer: (b) Scissors

Scissors is a class I lever because the fulcrum lies between the load and the effort.

Teacher's Note:
a) Class I levers have the fulcrum in the middle, whereas Class II levers have the load between the fulcrum and the effort.
b) Do not confuse nail cutters and bottle openers, which act as Class II levers with the load in the centre.

3. If the area of contact increases, then [1 Mark]
(a) Pressure decreases
(b) Pressure increases
(c) Pressure remains constant
(d) None of the above

Answer: (a) Pressure decreases

Pressure is inversely proportional to the area of contact for a given force (\( P = \frac{F}{A} \)).

Teacher's Note:
a) Emphasize that pressure decreases when surface area increases because the force is distributed over a larger region.
b) Watch out for students who think pressure is directly proportional to area.

4. A force which always tends to slow down the motion of an object on a surface is [1 Mark]
(a) Weight
(b) Inertia
(c) Gravity
(d) Friction

Answer: (d) Friction

Frictional force opposes relative motion between two surfaces in contact.

Teacher's Note:
a) Friction always acts in the direction opposite to the applied motion.
b) Inertia is a property of matter, not an applied force.

5. Why is it harder to slide a stationary heavy box across the floor than to keep it sliding? [1 Mark]
(a) Sliding friction is greater than the static friction.
(b) Sliding friction is less than rolling friction.
(c) Static friction is greater than sliding friction.
(d) Sliding friction is more than rolling friction.

Answer: (c) Static friction is greater than sliding friction.

Static friction locks surfaces together at microscopic levels more strongly than sliding friction.

Teacher's Note:
a) Maximum static friction must be overcome to start motion, which is harder than maintaining it.
b) Ensure students do not mistakenly select option (a) due to misreading.

6. Which of the following is not a fundamental unit? [1 Mark]
(a) Cubic metre
(b) Kilogram
(c) Metre
(d) Kelvin

Answer: (a) Cubic metre

Cubic metre is a derived unit for volume, while kilogram, metre, and kelvin are fundamental S.I. units.

Teacher's Note:
a) Fundamental units are independent units defined in the S.I. system.
b) Derived units are obtained by combining fundamental units.

7. Rubbing your palms together creates warmth due to: [1 Mark]
(a) Air in between the two palms
(b) Gravity
(c) Friction between the two palms
(d) All of the above

Answer: (c) Friction between the two palms

Mechanical energy is converted into thermal energy due to friction when palms are rubbed.

Teacher's Note:
a) Friction opposes motion and generates heat energy as a byproduct.
b) Students must realize that air and gravity do not cause this localized warming effect.

8. Two like magnetic poles: [1 Mark]
(a) Attract each other
(b) Repel each other
(c) Repel when close and attract when far from each other
(d) Attract when close and repel when far from each other

Answer: (b) Repel each other

Like poles (North-North or South-South) always repel each other.

Teacher's Note:
a) Opposite poles attract, while like poles repel.
b) Keep this fundamental rule of magnetism clear in mind.

9. The length having the largest magnitude out of the following options is [1 Mark]
(a) 5 cm
(b) 7 mm
(c) 4 km
(d) 6 m

Answer: (c) 4 km

Converting all values to millimetres: \( 5\text{ cm} = 50\text{ mm} \), \( 7\text{ mm} = 7\text{ mm} \), \( 4\text{ km} = 40,00,000\text{ mm} \), and \( 6\text{ m} = 6000\text{ mm} \). Thus, \( 4\text{ km} \) is the largest.

Teacher's Note:
a) Always convert quantities to a common unit before comparing magnitudes.
b) Remember that 1 kilometre equals 1000 metres.

10. The magnetism acquired by a magnetic material when it is kept near (or in contact with) a magnet, is called [1 Mark]
(a) Temporary magnetism
(b) Induced magnetism
(c) Permanent magnetism
(d) Induction

Answer: (b) Induced magnetism

The temporary magnetic property acquired by induction is known as induced magnetism.

Teacher's Note:
a) Induction is the phenomenon, but induced magnetism is the property acquired.
b) Read options carefully to distinguish between the process name and property name.

11. Water stored at a height in a dam possesses [1 Mark]
(a) Chemical energy
(b) Kinetic energy
(c) Potential energy
(d) Electrical energy

Answer: (c) Potential energy

Water at a height possesses gravitational potential energy due to its position.

Teacher's Note:
a) Energy possessed by a body due to its position or height is potential energy.
b) Once water starts flowing down, potential energy converts into kinetic energy.

12. Which of the following is not a non-contact force? [1 Mark]
(a) Frictional force
(b) Gravitational force
(c) Electrostatic force
(d) Magnetic force

Answer: (a) Frictional force

Frictional force requires physical contact between two surfaces, making it a contact force.

Teacher's Note:
a) Gravitational, electrostatic, and magnetic forces act without physical contact.
b) Ensure students look for the word "not" in such questions.

13. A block of weight 400 N is kept on the floor. The area of contact is \( 4\text{ m}^2 \). The pressure exerted by the box on the floor is [1 Mark]
(a) 200 Pa
(b) 400 Pa
(c) 300 Pa
(d) 100 Pa

Answer: (d) 100 Pa

Using the formula \( P = \frac{F}{A} = \frac{400\text{ N}}{4\text{ m}^2} = 100\text{ Pa} \).

Teacher's Note:
a) Apply the direct formula for pressure where force is weight and area is given in square metres.
b) Unit of pressure is Pascal (Pa) or \( \text{N/m}^2 \).

14. Every object in this universe, whether small or large exerts a force on every other object. What is the name of this force? [1 Mark]
(a) Electrostatic force
(b) Gravitational force
(c) Magnetic force
(d) Nuclear force

Answer: (b) Gravitational force

Universal law of gravitation states that every mass attracts every other mass in the universe.

Teacher's Note:
a) Gravitational force is a universal attractive force operating between all objects.
b) Do not confuse it with magnetic or electrostatic forces which require specific properties like charge or poles.

15. Calculate the distance between a man and a box when the work done to move the box was 100 J with a force of 15 N. [1 Mark]
(a) 16.6 m
(b) 26.6 m
(c) 6 m
(d) 6.6 m

Answer: (d) 6.6 m

Using formula \( W = F \times s \), we get \( s = \frac{W}{F} = \frac{100}{15} = 6.6\text{ m} \).

Teacher's Note:
a) Rearrange the work formula \( W = Fs \) to find displacement \( s \).
b) Check decimal division carefully to avoid calculation errors.

Question 2

(A) Name the following. [5]

1. Fundamental unit of temperature. [1 Mark]

Answer: kelvin

Teacher's Note:
a) Kelvin is the S.I. base unit for thermodynamic temperature.
b) Spell it correctly without degree symbols when referring to the base unit name.

2. Simplest machine. [1 Mark]

Answer: Lever

Teacher's Note:
a) A lever is considered the simplest mechanical machine.
b) Mentioning inclined plane is also accepted in some contexts, but lever is primary.

3. A quantity which depends on other quantities. [1 Mark]

Answer: Derived quantity

Teacher's Note:
a) Derived quantities are framed using fundamental quantities.
b) Examples include speed, area, and volume.

4. Time taken by the Earth to complete one rotation about its own axis. [1 Mark]

Answer: Mean solar day

Teacher's Note:
a) One complete rotation takes 24 hours, defining a mean solar day.
b) Distinguish clearly between rotation (day) and revolution (year).

5. Force of friction between a rolling object and surface. [1 Mark]

Answer: Rolling friction

Teacher's Note:
a) Rolling friction is significantly smaller than sliding friction.
b) It is the resistive force when an object rolls over a surface.

(B) Fill in the blanks. [5]

1. Electricity produced from water is called __________. [1 Mark]

Answer: Hydro-electricity

Teacher's Note:
a) Hydro-electricity harnesses potential energy of water stored in dams.
b) Ensure correct spelling of the compound term.

2. The normal temperature of the body is __________. [1 Mark]

Answer: \( 37^{\circ}\text{C} \)

Teacher's Note:
a) Normal human body temperature is \( 37^{\circ}\text{C} \) or \( 98.6^{\circ}\text{F} \).
b) Always include the unit \( ^{\circ}\text{C} \) in the answer.

3. To increase pressure, area of contact is __________. [1 Mark]

Answer: Decreased

Teacher's Note:
a) Pressure is inversely proportional to area, so decreasing area increases pressure.
b) Concepts like needles and sharp knives rely on this principle.

4. __________ is the surest test of magnetism. [1 Mark]

Answer: Repulsion

Teacher's Note:
a) Attraction can happen with unmagnetized iron, but repulsion occurs only between like poles.
b) Therefore, repulsion is the surest test.

5. Force of gravity is always directed towards the __________ of the Earth. [1 Mark]

Answer: Centre

Teacher's Note:
a) Gravitational pull is directed towards the centre of celestial bodies like the Earth.
b) This gives objects their weight downwards.

Question 3

(A) Match the following. [5]

Answer:
1. Volume - (a) \( \text{m}^3 \)
2. Heater - (b) Electrical to heat
3. Claw hammer - (c) Class I lever
4. Speed - (d) m/s
5. Photo voltaic cell - (e) Light to electrical

Teacher's Note:
a) Match physical quantities with correct units and devices with corresponding energy conversions.
b) A claw hammer serves as a classic example of a Class I lever.

(B) Correct the following sentences. [5]

1. An object can be measured with an accuracy of 0.01 mm with a vernier calliper. [1 Mark]

Answer: An object can be measured with an accuracy of 0.1 mm with a vernier calliper.

Teacher's Note:
a) The least count of a standard vernier calliper is 0.1 mm or 0.01 cm.
b) Verify measurement limits of common laboratory instruments.

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

Answer: A class II lever has load in the middle.

Teacher's Note:
a) Class I levers have the fulcrum in the middle.
b) Class II levers have the load positioned between the fulcrum and the effort.

3. Weight of an object is the force with which an object gets attracted towards the ground. [1 Mark]

Answer: Weight of an object is the force with which the object gets attracted towards the centre of the earth.

Teacher's Note:
a) Gravitational force acts towards the centre of the Earth, not just a vague ground surface.
b) Emphasize precision in definitions.

4. Static friction is lesser than sliding friction and greater than rolling friction. [1 Mark]

Answer: Static friction is greater than sliding friction and rolling friction.

Teacher's Note:
a) Static friction is always the highest among the three types of friction.
b) Order of magnitude: Static friction > Sliding friction > Rolling friction.

5. In a solar cell, light energy is converted to heat energy. [1 Mark]

Answer: In a solar cell, light energy is converted to electric energy.

Teacher's Note:
a) Solar cells generate electricity directly from sunlight via photovoltaic action.
b) Do not confuse them with solar heaters which convert light to heat energy.

Question 4

(A) [5]

1. What are derived units? [1 Mark]

Answer: The units of derived quantities which can be expressed as a combination of basic units are called derived units.

Teacher's Note:
a) Derived units depend directly on fundamental base units.
b) Examples include \( \text{m}^2 \) for area and \( \text{m}^3 \) for volume.

2. How many base units are there in S.I. system? [1 Mark]

Answer: There are seven base units in the S.I. system.

Teacher's Note:
a) The seven base quantities are length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity.
b) Memorize the complete list for comprehensive physics foundations.

3. Name the larger units of length? [1 Mark]

Answer: Astronomical unit and light year.

Teacher's Note:
a) Larger units are used to measure astronomical distances in space.
b) A light year is the distance travelled by light in one year.

4. Name the shorter units of length? [1 Mark]

Answer: Angstrom and nanometre.

Teacher's Note:
a) Shorter units measure microscopic dimensions like atomic sizes and wavelengths.
b) \( 1\text{ Å} = 10^{-10}\text{ m} \) and \( 1\text{ nm} = 10^{-9}\text{ m} \).

5. What is parallax? [1 Mark]

Answer: The apparent change in position of an object with respect to a point when viewed with left and right eye is known as parallax.

Teacher's Note:
a) Parallax error occurs when readings are not viewed perpendicular to the scale.
b) Proper eye alignment eliminates parallax.

(B) A girl of mass 50 kg is standing on pencil heels each of area of cross-section \( 1\text{ cm}^2 \) and an elephant of mass 5000 kg and foot area \( 250\text{ cm}^2 \) each, are standing on a floor. Which one will exert more pressure and what is the difference between the pressure exerted by the girl and the elephant? [5 Marks]

Answer:
Weight of the girl = \( 50\text{ kgf} = 50 \times 10 = 500\text{ N} \)
Area of the heels = \( 2 \times 1\text{ cm}^2 = 2\text{ cm}^2 = \frac{2}{10000}\text{ m}^2 \)
Pressure exerted by the girl = \( \frac{W}{A} = \frac{500}{\left(\frac{2}{10000}\right)} = 25,00,000\text{ Pa} \)
Weight of the elephant = \( 5000\text{ kgf} = 5000 \times 10 = 50,000\text{ N} \)
Area of the feet = \( 4 \times 250\text{ cm}^2 = 1000\text{ cm}^2 = \frac{1000}{10000}\text{ m}^2 = 0.1\text{ m}^2 \)
Pressure exerted by the elephant = \( \frac{W}{A} = \frac{50000}{0.1} = 5,00,000\text{ Pa} \)
Difference in pressure = \( 25,00,000\text{ Pa} - 5,00,000\text{ Pa} = 20,00,000\text{ Pa} \).
Thus, the girl will exert more pressure.

Teacher's Note:
a) Convert areas from square centimetres to square metres by dividing by \( 10,000 \) before computing pressure.
b) Notice how a smaller area results in extremely high pressure even with smaller weight.

Question 5

(A) Answer in one sentence: [5]

1. Why do all machines require proper care and maintenance? [1 Mark]

Answer: All machines require proper care and maintenance for their efficient and longer use.

Teacher's Note:
a) Maintenance reduces friction and wear and tear of moving parts.
b) Keeps operational efficiency at optimal levels.

2. Define 1 Joule of work. [1 Mark]

Answer: 1 Joule is the amount of work done, when a force of 1 newton displaces a body by 1 metre along the line of action of force.

Teacher's Note:
a) Formula: \( W = F \times s \).
b) Ensure both units (Newton and metre) are explicitly mentioned.

3. When do we say that work is done? [1 Mark]

Answer: Work is said to be done when a force acts on an object and as a result of this force the object gets displaced from its initial position.

Teacher's Note:
a) Both force application and displacement in the direction of force are mandatory.
b) If displacement is zero, work done is zero.

4. What is volume? What is its unit? [1 Mark]

Answer: The space occupied by an object is known as its volume. Its S.I. unit is metre-cubed (\( \text{m}^3 \)).

Teacher's Note:
a) Volume measures three-dimensional space capacity.
b) Standard S.I. unit is cubic metre.

5. Name the force in action when a potter turns his wheel. [1 Mark]

Answer: When the potter turns his wheel, he applies muscular force.

Teacher's Note:
a) Muscular force is a contact force exerted by skeletal muscles.
b) Common everyday actions involve muscular force.

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

1. Iron, nickel, cobalt, aluminium [1 Mark]

Answer: Aluminium

Teacher's Note:
a) Aluminium is a non-magnetic substance, while iron, nickel, and cobalt are magnetic substances.
b) Identify material properties correctly.

2. Length, mass, area, time [1 Mark]

Answer: Area

Teacher's Note:
a) Area is a derived quantity, whereas length, mass, and time are fundamental quantities.
b) Distinguish between base and derived physical quantities.

3. kelvin, volta, celsius, Fahrenheit [1 Mark]

Answer: volta

Teacher's Note:
a) Volta is a unit of electric potential, whereas kelvin, celsius, and Fahrenheit measure temperature.
b) Watch out for spelling variations in units.

4. Magnetic force, gravitational force, electrostatic force, frictional force [1 Mark]

Answer: Frictional force

Teacher's Note:
a) Frictional force is a contact force, whereas magnetic, gravitational, and electrostatic forces are non-contact forces.
b) Classify forces based on contact requirements.

5. Making pores, using lubricants, polishing, using ball bearings [1 Mark]

Answer: Making pores

Teacher's Note:
a) Making pores increases friction, while using lubricants, polishing, and using ball bearings decrease friction.
b) Understand methods used to manage friction.

Question 6

(A) What is magnetic induction? Explain with the help of a diagram. [5 Marks]

Answer:
The property by which an ordinary piece of iron acquires magnetic properties due to the presence of another magnet is called magnetic induction.
[Figure: Setup showing iron pins on a stand base near an iron nail, a bar magnet touching the top head of the nail, and pins clinging to the lower tip of the nail by induction.]
Spread some iron pins on the base of a stand. These pins are not attracted to the nail. When a magnet is touched to the head of the nail, some pins at the base of the stand cling to the nail. This is because the nail turns into a magnet, and hence, acquires the property of magnetism. This is magnetic induction. When the magnet is removed from the head of the nail, the pins fall down showing de-magnetism. Hence, the nail acquires magnetism and pins get attracted to it by induction.

Teacher's Note:
a) Emphasize that magnetic induction precedes attraction in unmagnetized magnetic materials.
b) Explain that induced magnetism is temporary and disappears when the inducing magnet is removed.

(B) Define the following. [5]

1. One kilogram [1 Mark]

Answer: It is defined as the mass of a cylinder of platinum-irridium alloy kept at International Bureau of Weights and Measures in Paris.

Teacher's Note:
a) Mention the standard prototype mass reference.
b) Note that standard definitions have recently evolved towards fundamental constants, but this remains standard school level definition.

2. Muscular force [1 Mark]

Answer: Muscular force is the force produced by the muscles of living beings.

Teacher's Note:
a) It is a contact force used for lifting, pushing, and pulling objects.
b) Both humans and animals exert muscular force.

3. Pressure [1 Mark]

Answer: The force acting per unit surface area is called pressure.

Teacher's Note:
a) Formula: \( P = \frac{F}{A} \).
b) S.I. unit is Pascal (Pa).

4. Length of a magnet [1 Mark]

Answer: The total distance between the North Pole to the centre and the centre to the South Pole of a magnet is called the length of a magnet.

Teacher's Note:
a) Magnetic length is slightly less than the geometrical length of a bar magnet.
b) Poles lie slightly inside the geometric ends.

5. Efficiency [1 Mark]

Answer: Efficiency is the ratio of work done by the machine to the work done on the machine.

Teacher's Note:
a) Efficiency indicates how effectively a machine converts input work into useful output work.
b) Usually expressed as a percentage.

Question 7

(A) Answer the following.

1. Define Kinetic energy and Potential energy? [2 Marks]

Answer:
Kinetic energy: Kinetic energy is the energy possessed by a body by virtue of its motion. It is given by the formula: \( \text{K.E} = \frac{1}{2}mv^2 \).
Potential energy: Potential energy is the energy possessed by a body by virtue of its position with reference of the Earth. It is given by the formula: \( \text{P.E} = mgh \).

Teacher's Note:
a) Clearly distinguish between motion-based energy (kinetic) and position-based energy (potential).
b) State equations with standard symbols (\( m \), \( v \), \( g \), \( h \)).

2. What are the effects of force? [3 Marks]

Answer:
The effects of force are as follows:
1. A force can make a stationary object move.
2. A force can stop a moving object.
3. A force can change the direction of a moving object.
4. A force can change the speed of a moving object.
5. A force can change the shape and size of an object.

Teacher's Note:
a) List at least three to five distinct effects for full credit.
b) Provide clear real-world examples for each effect if required.

(B) Answer the following.

1. What is friction? Write any two advantages of friction? [2 Marks]

Answer:
Friction is the resistance to motion experienced when two surfaces in contact move with respect to each other.
The following are the advantages of friction:
1. It is due to friction that we can walk without slipping.
2. We can hold a pen or a pencil and write due to friction.

Teacher's Note:
a) Define friction as an opposing contact force.
b) Give everyday practical examples where friction is helpful.

2. What is a screw? Give three uses of screws. [3 Marks]

Answer:
A screw is a rotating (winding) inclined plane.
The following are the three uses of a screw:
1. It is used to hold two pieces of wood or metal tightly.
2. Screw jack is used for lifting a car or a truck, in order to change a punctured wheel.
3. A cork screw is used for pulling out a cork from the bottles of wine or ketchup.

Teacher's Note:
a) Describe the screw as an inclined plane wrapped around a cylinder.
b) List distinct practical applications clearly.