Class 9 Physics Important Short Questions (All Chapters)

Q: Q1: Are these questions 100% accurate according to the new Punjab Board syllabus?

Ans: Yes, absolutely. These questions have been extracted from the official new Punjab Curriculum and Textbook Board (PCTB) book.

Q: Q2: Why do cricketers pull their hands backward while catching a fast-moving cricket ball?

Ans: This is a classic application of Impulse and Momentum. A fast ball has high momentum. To stop it, we need to change its momentum to zero. By pulling hands backward, the fielder increases the impact time (Δt). Since Force is inversely proportional to time (F=Δp/Δt), increasing the time drastically reduces the impact force on the hands, preventing injury.

Q: Q3: What is the actual difference between Mass and Weight?

Ans: Mass : The amount of matter in a body. It is a scalar quantity , is constant everywhere, and its SI unit is the kilogram (kg). Weight : The force of gravity acting on that mass (W=mg). It is a vector quantity , changes with location (e.g., less on the moon), and its SI unit is the Newton (N).

Q: Q4: How does a sharp knife cut better than a blunt one?

Ans: Pressure depends on Force and Area (P=F/A). A sharp knife has a very thin edge, which means the surface area is extremely small . For the same applied force, the pressure exerted by the sharp knife is enormously high, allowing it to cut through objects easily.

Q: Q5: Why doesn't an astronaut feel heavy on the Moon?

Ans: The Moon has less mass than Earth, resulting in a weaker gravitational field strength (g=1.6m/s2 on the moon vs 10m/s2 on Earth). Since weight (W=mg) depends on 'g', the weight of the astronaut decreases by 6 times on the moon, even though their mass remains exactly the same.

Q: Q6: Is it possible for an object to have acceleration but zero velocity?

Ans: Yes. When you throw a ball vertically upward, at the very highest point, the velocity momentarily becomes zero . However, gravity (g=10m/s2) is still acting on it downward, so its acceleration is not zero .

Are you looking for the Class 9 Physics Important Short Questions for the exams? You’ve come to the right place.

We have compiled a complete list of high-weightage short questions for 9th-grade Physics, based on the latest syllabus of the Punjab boards. This guide will help you focus your revision and score maximum marks.

Class 9 Physics Short Questions Chapterwise

Download the important short questions in PDF below

📖 Chapter 1: Physical Quantities and Measurement

Q1: Can a non-physical quantity be measured? If yes, then how?
Q2: Differentiate between physical and non-physical quantities.
Q3: Does a non-physical quantity have dimensions?
Q4: What is measurement? Name its two parts.
Q5: Write the names of 3 base quantities and 3 derived quantities.
Q6: Differentiate between base and derived quantities.
Q7: Why do we need a standard unit for measurements?
Q8: Write the names and symbols of all SI base units.
Q9: Why are prefixes used? Name three sub-multiple and three multiple prefixes with their symbols.
Q10: Express the unit of pressure “pascal” in some other units.
Q11: What are the key rules for writing SI unit symbols and prefixes correctly?
Q12: Define base units. Give two examples.
Q13: Define prefixes. Give two examples.
Q14: Convert 3,500,000,000 Hz into MHz and 0.00003 g into µg by using prefixes.
Q15: Why is a standard unit needed to measure a quantity correctly?
Q16: Express the following in scientific notation: (a) 0.45 m (b) 0.004 kg (c) 186000 s
Q17: Define scientific notation with an example.
Q18: Write in standard form: (i) 384,000,000 m (ii) 0.00045 s
Q19: What is meant by zero error?
Q20: Define measuring tape and write its least count.
Q21: What are the essential laboratory safety rules to follow during experiments?
Q22: Define least count and measuring instrument. Give an example.
Q23: Differentiate between base and derived units.
Q24: Define least count. Write the least count of a metre rule.
Q25: Why does parallax error occur?
Q26: How many divisions are there on a Vernier scale?
Q27: Write four rules of laboratory safety.
Q28: Define the pitch of a micrometer screw gauge.
Q29: For what purpose is a micrometer screw gauge used?
Q30: Why does a micrometer screw gauge measure more accurately than Vernier Callipers?
Q31: Why is it better to place the object close to the metre scale?
Q32: Differentiate between systematic and random errors.
Q33: Round off to 2 significant figures: (i) $4.45 \times 10^{2} m$ 4.45×102m (ii) $4.55 \times 10^{2} m$ 4.55×102m
Q34: Define scalar and vector quantities.
Q35: State the head-to-tail rule for addition of vectors.
Q36: Differentiate between circular motion and rotatory motion.
Q37: Define uniform and non-uniform velocities.
Q38: What is a resultant vector?
Q39: Who discovered relativity?
Q40: Is it possible for a body to have acceleration when moving with (i) constant velocity (ii) constant speed?
Q41: Define Mechanics. Name its branches.
Q42: Define kinematics.
Q43: Write the symbolic representation methods of vectors.
Q44: Define resultant vector.
Q45: How are vector quantities important in our daily life?
Q46: Explain briefly that the state of rest and motion is relative.

📖 Chapter 2: Kinematics

Q47: Differentiate between speed and velocity.
Q48: Describe the SI unit of distance and displacement.
Q49: A body moving with uniform speed — will its velocity be uniform? Give reason.
Q50: A car moving on a circular road may have constant speed, but its velocity is changing at every instant. Why?
Q51: Define instantaneous speed.
Q52: A player covers 80m in 10 seconds. Find the average speed.
Q53: An eagle dives to the ground along a 300m path with an average speed of 60m/s. How long does it take?
Q54: Is it possible that the velocity of an object is zero at an instant, but its acceleration is not zero? Give an example.
Q55: Define acceleration. Give its formula.
Q56: Define positive and negative acceleration.
Q57: What is retardation?
Q58: What are distance-time and speed-time graphs?
Q59: Define graph.
Q60: Speed of a car is 72 km/h. Convert this to m/s.
Q61: Convert m/s to km/h.
Q62: Write the three equations of motion.
Q63: Falling objects near Earth have the same constant acceleration. Does this mean a heavier object falls faster than a lighter one?
Q64: What is meant by the universal speed limit?
Q65: Write three equations of motion under gravity.

📖 Chapter 3: Dynamics

Q66: What kind of change in motion may be produced by a force?
Q67: Give 5 examples of contact forces.
Q68: Define the common concept of force with an example.
Q69: Differentiate between electrostatic and magnetic field.
Q70: What are strong and weak nuclear forces?
Q71: Define contact forces with an example.
Q72: Differentiate between friction and drag force.
Q73: Differentiate between normal force and tension.
Q74: Define air resistance.
Q75: What is elastic force? Give examples.
Q76: Define gravitational force with an example.
Q77: Differentiate between electrostatic force and magnetic force.
Q78: An object moves with constant velocity in free space. How long will it continue to move with this velocity?
Q79: Why has Newton’s first law not been proved on Earth?
Q80: When sitting in a car that suddenly accelerates, you are pushed back into the seat. Why?
Q81: State Newton’s first law of motion.
Q82: State Newton’s third law of motion.
Q83: When a bus suddenly starts, passengers fall backward. Explain why.
Q84: Derive $F = m a$ F=ma from Newton’s second law.
Q85: When someone jumps from a small boat onto the river bank, why does the jumper often fall into the water?
Q86: Write the difference between mass and weight.
Q87: A 10 kg block moves on a frictionless horizontal surface with an acceleration of $2 m / s^{2}$ 2 m/s2. What is the force acting on the block?
Q88: Define gravitational field strength.
Q89: Write the value of gravitational field strength.
Q90: Define terminal velocity of an object.
Q91: Differentiate between friction and kinetic friction.
Q92: Define rolling friction.
Q93: Define streamline flow.
Q94: Why doesn’t water form a wet layer between the tyre surface and the road, and how does this reduce skidding?
Q95: How does a wheel produce a frictional force when it contacts the surface?
Q96: How does a hovercraft move over both water and ground?
Q97: Define sliding friction. Name its categories.
Q98: Differentiate between static friction and kinetic friction.
Q99: State the law of conservation of linear momentum.
Q100: Differentiate between impulse and momentum.
Q101: A bullet of mass 15 g is fired with a velocity of 150 m/s. What is its momentum?
Q102: How do crumple zones in automobiles help protect passengers during an accident?
Q103: What is a seat belt, and how does it help protect passengers in a car?
Q104: A person falling on a cemented floor gets badly hurt. Explain why.
Q105: A cricket player draws back his hands while catching a ball. Explain why.
Q106: State Newton’s second law of motion in terms of momentum.
Q107: What is the advantage of air bags over seat belts in terms of momentum?
Q108: When a cricket ball hits high, a fielder draws hands backward while catching it. Why?
Q109: Define system and isolated system.
Q110: State the law of conservation of momentum.
Q1 (Turning Effect): Define like and unlike parallel forces.
Q2 (Turning Effect): Difference between like and unlike parallel forces.
Q3 (Turning Effect): Differentiate between like parallel forces and unlike parallel forces.
Q4 (Turning Effect): A ripe mango does not normally fall from the tree, but when the branch is shaken, it falls easily. Why?
Q5 (Turning Effect): Define resultant force.
Q6 (Turning Effect): Explain the head-to-tail rule.

📖 Chapter 4: Turning Effect of Forces

Q7 (Turning Effect): What is the line of action of a force?
Q8 (Turning Effect): Define couple and give an example.
Q9 (Turning Effect): Define turning effect of a force (torque) with examples.
Q10 (Turning Effect): Differentiate between line of action of force and moment arm.
Q11 (Turning Effect): Give a real-life example of torque.
Q12 (Turning Effect): Why are steering wheels of smaller diameter installed in modern vehicles?
Q13 (Turning Effect): What are rectangular components of a vector and their values?
Q14 (Turning Effect): What is resolution of force?
Q15 (Turning Effect): Define rectangular components of a force.
Q16 (Turning Effect): Can a rectangular component of a vector be greater than the resultant vector?
Q17 (Turning Effect): How does a tightrope walker balance himself?
Q18 (Turning Effect): State the principle of moments.
Q19 (Turning Effect): Differentiate between clockwise and anticlockwise moment.
Q20 (Turning Effect): Give an example of a body that is moving yet in equilibrium.
Q21 (Turning Effect): Differentiate between static and dynamic equilibrium.
Q22 (Turning Effect): State the first condition of equilibrium.
Q23 (Turning Effect): State the second condition of equilibrium.
Q24 (Turning Effect): Define stable equilibrium.
Q25 (Turning Effect): Define unstable equilibrium.
Q26 (Turning Effect): Define neutral equilibrium with an example.
Q27 (Turning Effect): Define centripetal force. Write its formula and direction.
Q28 (Turning Effect): Define centripetal acceleration and write its equation.

📖 Chapter 5: Work, Energy and Power

Q29: What is the work done on an object that remains at rest when a force is applied to it?
Q30: Define work and its SI unit.
Q31: Define efficiency of a working system. Why can’t a system have 100% efficiency?
Q32: A person does 200 J of work pushing a carton through 5 m. How much force is applied?
Q33: Find the work done by a 65 N force pulling a suitcase 20 m (at 30° to horizontal).
Q34: A 120 N block is dragged up a 20 m slope with a force of 100 N to lift it 10 m. Calculate the efficiency.
Q35: Discuss the case when work done is maximum.
Q36: How is work done if a 4 kg brick is pulled up a height of 5m?
Q37: Define the SI unit of work. Also discuss its bigger units.
Q38: A person does 200 J of work pushing a carton through 5 m. How much force is applied?
Q39: A slow-moving car may have more kinetic energy than a fast-moving motorcycle. How is this possible?
Q40: A woman gains 4500 J of gravitational PE running up stairs. If she runs up with twice the speed, what will her PE gain be?
Q41: Find an expression for the kinetic energy of a moving body.
Q42: What is gravitational potential energy? Give an example.
Q43: Describe the conservation of energy.
Q44: Difference between nuclear energy and chemical energy.
Q45: Difference between gravitational potential energy and nuclear energy.
Q46: According to Einstein’s theory of relativity, how are matter and energy related?
Q47: A 10 kg body is raised to a height of 5 m. Find its gravitational potential energy.
Q48: In which form is energy stored in a stretched bow?
Q49: Differentiate between kinetic energy and potential energy.
Q50: What is the energy content of the nuclear bomb dropped on Hiroshima?
Q51: Describe the energy output of a power station in one year.
Q52: Write the formula and SI unit of potential energy.
Q53: Differentiate between gravitational potential energy and elastic potential energy.
Q54: Differentiate between chemical potential energy and nuclear potential energy.
Q55: Comment on the statement: “An object has one joule of potential energy.”
Q56: State the law of conservation of energy.
Q57: What is meant by waste energy?
Q58: Difference between renewable and non-renewable energy.
Q59: Describe two advantages of energy production.
Q60: Write two disadvantages of energy production.
Q61: Name some non-renewable energy sources.
Q62: What is power? Define the unit used for it.
Q63: What do you know about the watt?
Q64: What is the unit of power in the British engineering system?
Q65: Calculate the power of a machine that does 4 J of work in 2 seconds.
Q66: Difference between output and input energy.
Q67: Why is the energy output always less than the energy input?
Q68: A cyclist does 12 J of useful work from every 80 J of food energy. Find his % efficiency.
Q69: Why doesn’t an ideal system exist in daily life?

📖 Chapter 6: Properties of Matter (Mechanical Properties)

Q70: State what you mean by elasticity of a solid.
Q71: Describe deformation of solids with an example.
Q72: Steel is more elastic than rubber. Why?
Q73: Write four differences between the solid and gas states of matter.
Q74: Define deforming force.
Q75: Describe any two applications of Hooke’s law.
Q76: Difference between galvanometer and spring scales.
Q77: Define elastic limit and Hooke’s law.
Q78: What is spring constant? Write its SI unit.
Q79: Give names of three applications of Hooke’s law.
Q80: Springs are made of steel instead of iron. Why?
Q81: Why do heavy animals like elephants have a large foot area?
Q82: Why is it painful to walk barefoot on pebbles?
Q83: Distinguish between force and pressure.
Q84: Describe any two examples of pressure in daily life.
Q85: Why do sports boots have studs on their soles?
Q86: A girl walking on a carpet in high heels leaves deep impressions. Why?
Q87: Why is the cutting edge of a knife made very thin?
Q88: Why are water tanks constructed at the highest level in houses?
Q89: Define pressure. Write its formula and unit.
Q90: What is one pascal?
Q91: What is the relationship between liquid pressure and depth?
Q92: Calculate the pressure of a column of mercury 76cm high (density of mercury $= 13.6 \times 10^{3} k g / m^{3}$ =13.6×103kg/m3).
Q93: Describe atmospheric pressure.
Q94: Which instrument measures atmospheric pressure?
Q95: How does a change in atmospheric pressure relate to weather?
Q96: Define atmospheric pressure.
Q97: Explain the effect of variation of atmospheric pressure with height.
Q98: State Pascal’s law. Give an application.
Q99: State the basic principle used in the hydraulic brake system of automobiles.
Q100: Define force multiplier.
Q101: Define hydraulic brake.
Q102: Write the advantages of Pascal’s law.
Q103: Write the uses of a hydraulic press.

📖 Chapter 7: Thermal Properties of Matter

Q1 (Thermal): What is the effect of raising the temperature of a liquid?
Q2 (Thermal): What is meant by the temperature of a body?
Q3 (Thermal): What determines the direction of heat flow?
Q4 (Thermal): Distinguish between heat and internal energy.
Q5 (Thermal): Relation between temperature and internal energy.
Q6 (Thermal): Differentiate between temperature and heat.
Q7 (Thermal): Why does heat energy transfer from one thing to another?
Q8 (Thermal): Why does a cup of tea get cold after some time?
Q9 (Thermal): Discuss whether the Sun is matter.
Q10 (Thermal): What is meant by thermometric property? List some thermometric properties.
Q11 (Thermal): Describe the main scales used for measuring temperature.
Q12 (Thermal): Write down basic thermometric properties.
Q13 (Thermal): Explain the liquid-in-glass thermometer.
Q14 (Thermal): Differentiate between upper and lower fixed points.
Q15 (Thermal): Define the Fahrenheit scale and label its fixed points.
Q16 (Thermal): Define the absolute (Kelvin) temperature scale.
Q17 (Thermal): Explain the relationship between Kelvin and Celsius scales.
Q18 (Thermal): How much would 30°C be on the Fahrenheit and Kelvin scales?
Q19 (Thermal): Define thermocouple thermometer.
Q20 (Thermal): Why are the walls of a thermometer bulb thin?
Q21 (Thermal): What are thermometric properties?
Q22 (Thermal): Define absolute zero. What is its value?
Q23 (Thermal): Why does current flow in a thermocouple thermometer?
Q24 (Thermal): Why is mercury usually preferred to alcohol as a thermometric liquid?
Q25 (Thermal): Why are there no negative numbers on the Kelvin scale?

📖 Chapter 8: Magnetism

Q26: Define magnetism with examples.
Q27: Differentiate between magnetic and non-magnetic materials.
Q28: Define magnet. How many properties does a magnet have?
Q29: Difference between north and south magnetic poles.
Q30: Define magnetic pole and attraction/repulsion of magnetic poles.
Q31: Define induced magnetism.
Q32: Define magnetised and unmagnetised.
Q33: Describe the direction of internal and external magnetic field lines.
Q34: Define magnetization.
Q35: What are temporary and permanent magnets?
Q36: Difference between temporary and permanent magnets.
Q37: Define the magnetic field of a magnet.
Q38: What are magnetic lines of force?
Q39: Define magnetic line of force.
Q40: How does a magnetic field work?
Q41: What determines the strength of a magnetic field?
Q42: Which material is used for temporary magnets?
Q43: Describe the relation between magnetic field strength and magnetic lines of force.
Q44: Name some uses of permanent magnets and electromagnets.
Q45: Define an A.C. generator.
Q46: Define one application of a permanent magnet.
Q47: Define moving coil loudspeaker.
Q48: What is the reverse process of an electric generator?
Q49: Describe the use of permanent magnets in flour mills.
Q50: Write the use of permanent magnets in the medical field.
Q51: Define uses of electromagnets.
Q52: Define the circuit breaker.
Q53: Explain the use of electromagnets in maglev trains.
Q54: State some uses of electromagnets.
Q55: What is a magnetic relay?
Q56: Difference between magnetisation and demagnetisation.
Q57: Describe the single-touch and double-touch methods.
Q58: Define heating and hammering as demagnetisation methods.
Q59: State the right-hand grip rule.
Q60: Write the stroking method of magnetisation.
Q61: Name the methods of demagnetisation of magnets.

📖 Chapter 9: Nature of Science

Q62: State what science is, in your own words. Write its two main groups.
Q63: What is physics all about? Name some of its branches.
Q64: Write the scope of physics.
Q65: Explain the concept of the theory of relativity.
Q66: What is the difference between geophysics and climate physics?
Q67: State some uses of physics in daily life.
Q68: Differentiate between mechanics and quantum mechanics.
Q69: Define heat and thermodynamics.
Q70: Differentiate between acoustics and optics.
Q71: Define relativistic mechanics.
Q72: Differentiate between biophysics and biomedical physics.
Q73: Differentiate between astrophysics and geophysics.
Q74: List the main steps of the scientific method.
Q75: What is a hypothesis? Give an example.
Q76: Distinguish between a theory and a law of physics.
Q77: Differentiate between theory and law.
Q78: Is the theory of science an ultimate truth?
Q79: When is a theory rejected or in need of modification?
Q80: If a hypothesis is not testable, is it wrong?

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❓ Frequently Asked Questions (FAQs)

Q1: Are these questions 100% accurate according to the new Punjab Board syllabus?

Ans: Yes, absolutely. These questions have been extracted from the official new Punjab Curriculum and Textbook Board (PCTB) book.

Q2: Why do cricketers pull their hands backward while catching a fast-moving cricket ball?

Ans: This is a classic application of Impulse and Momentum. A fast ball has high momentum. To stop it, we need to change its momentum to zero. By pulling hands backward, the fielder increases the impact time ( $Δ t$ ). Since Force is inversely proportional to time ( $F = Δ p / Δ t$ ), increasing the time drastically reduces the impact force on the hands, preventing injury.

Q3: What is the actual difference between Mass and Weight?

Ans:
Mass: The amount of matter in a body. It is a scalar quantity, is constant everywhere, and its SI unit is the kilogram (kg).
Weight: The force of gravity acting on that mass ( $W = m g$ ). It is a vector quantity, changes with location (e.g., less on the moon), and its SI unit is the Newton (N).

Q4: How does a sharp knife cut better than a blunt one?

Ans: Pressure depends on Force and Area ( $P = F / A$ ). A sharp knife has a very thin edge, which means the surface area is extremely small. For the same applied force, the pressure exerted by the sharp knife is enormously high, allowing it to cut through objects easily.

Q5: Why doesn’t an astronaut feel heavy on the Moon?

Ans: The Moon has less mass than Earth, resulting in a weaker gravitational field strength ( $g = 1.6 m / s^{2}$ on the moon vs $10 m / s^{2}$ on Earth). Since weight ( $W = m g$ ) depends on ‘g’, the weight of the astronaut decreases by 6 times on the moon, even though their mass remains exactly the same.

Q6: Is it possible for an object to have acceleration but zero velocity?

Ans: Yes. When you throw a ball vertically upward, at the very highest point, the velocity momentarily becomes zero. However, gravity ( $g = 10 m / s^{2}$ ) is still acting on it downward, so its acceleration is not zero.

Important Short Questions of Class 9

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Class 9 Physics Short Questions Chapterwise