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Physics Level 4 study materials
Physics Level 4 study resources

Physics Level 4 practice questions

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Question 1Question paper

Which quantity is a scalar?

  1. Displacement
  2. Velocity
  3. Speed Correct answer.
  4. Acceleration

Explanation

A scalar is fully described by magnitude alone, with no direction attached. Speed has only a magnitude, so it is a scalar quantity. Displacement, velocity and acceleration all require a stated direction, making them vectors.

Question 2Question paper

A car travels 150 m in 10 s at constant speed. What is its speed?

  1. 1.5 m/s
  2. 15 m/s Correct answer.
  3. 0.067 m/s
  4. 1500 m/s

Explanation

For constant speed, speed equals distance divided by time. Dividing 150 m by 10 s gives 15 m/s. The units follow directly from metres divided by seconds.

Question 3Question paper

Which statement describes Newton's first law correctly?

  1. Every action has an equal and opposite reaction.
  2. An object stays at rest or moves uniformly unless a resultant force acts. Correct answer.
  3. Force equals mass times acceleration.
  4. The total momentum of a closed system is constant.

Explanation

Newton's first law states that a body remains at rest or continues at constant velocity unless a resultant external force acts on it. It is often called the law of inertia. The other statements are the second and third laws, or the conservation of momentum.

Question 4Question paper

What is the SI unit of electrical resistance?

  1. Ampere
  2. Volt
  3. Ohm Correct answer.
  4. Coulomb

Explanation

Resistance is defined as the ratio of potential difference to current, so its unit is the volt per ampere, called the ohm. The ohm is the SI unit of resistance.

Question 5Question paper

Which of these is a transverse wave?

  1. A compression pulse in a spring
  2. A sound wave in water
  3. Sound travelling through air
  4. Light travelling in a vacuum Correct answer.

Explanation

In a transverse wave the oscillations are perpendicular to the direction of energy transfer, which is the case for electromagnetic waves such as light. Sound waves in fluids are longitudinal, with oscillations along the direction of travel.

Question 6Question paper

What is the approximate value of the acceleration of free fall near Earth's surface?

  1. 1.6 m/s²
  2. 9.8 m/s² Correct answer.
  3. 98 m/s²
  4. 0.98 m/s²

Explanation

Near Earth's surface the gravitational field strength is about 9.8 N/kg, so freely falling objects accelerate at roughly 9.8 m/s² downward. This value is often rounded to 10 m/s² in rough calculations.

Question 7Question paper

Which form of energy is stored in a stretched elastic band?

  1. Thermal energy
  2. Elastic potential energy Correct answer.
  3. Nuclear energy
  4. Chemical energy

Explanation

Work done in stretching or compressing an elastic object is stored as elastic potential energy. Releasing the band converts this stored energy back into kinetic energy.

Question 8Question paper

A lever is used to lift a load with a small effort. Which statement about a lever is correct?

  1. It multiplies the force but the work done cannot be reduced. Correct answer.
  2. It removes the need for any applied force.
  3. It reduces the total energy needed to lift the load.
  4. It always increases the distance moved by the load.

Explanation

A lever is a simple machine that can magnify an applied force by increasing the distance over which the effort acts. Because energy is conserved, the work done cannot be reduced below the useful work output. A real lever also wastes some energy as heat.

Question 9Question paper

A 2 kg object accelerates at 3 m/s². What resultant force acts on it?

  1. 6 N Correct answer.
  2. 5 N
  3. 12 N
  4. 1.5 N

Explanation

Newton's second law gives resultant force as mass times acceleration. Multiplying 2 kg by 3 m/s² yields 6 N. The unit newton is defined as one kilogram metre per second squared.

Question 10Question paper

A 1200 kg car moving at 20 m/s brakes to rest in 8 s. What is the magnitude of the average braking force?

  1. 96000 N
  2. 150 N
  3. 3000 N Correct answer.
  4. 2400 N

Explanation

The deceleration is the change in velocity divided by time, 20 m/s ÷ 8 s = 2.5 m/s². Applying F = ma gives 1200 kg × 2.5 m/s² = 3000 N. The force opposes the motion.

Question 11Question paper

A stone is dropped from rest and falls for 3 s, ignoring air resistance. Taking g = 10 m/s², how far does it fall?

  1. 15 m
  2. 45 m Correct answer.
  3. 30 m
  4. 90 m

Explanation

For motion from rest under constant acceleration, distance equals half the acceleration times the square of the time. That gives 0.5 × 10 × 3² = 45 m. The final speed would be 30 m/s, but distance uses the squared time.

Question 12Question paper

A 0.5 kg ball moving at 4 m/s strikes a wall and rebounds at 3 m/s. What is the magnitude of its change in momentum?

  1. 2.0 kg m/s
  2. 0.5 kg m/s
  3. 3.5 kg m/s Correct answer.
  4. 7.0 kg m/s

Explanation

Momentum is mass times velocity, and reversal changes the sign. Initial momentum is 0.5 × 4 = 2.0 kg m/s one way; final is 0.5 × (−3) = −1.5 kg m/s. The change is 2.0 − (−1.5) = 3.5 kg m/s in magnitude.

Question 13Question paper

A 60 W lamp is switched on for 5 minutes. How much energy does it transfer?

  1. 300 J
  2. 12 J
  3. 18000 J Correct answer.
  4. 3000 J

Explanation

Energy transferred equals power multiplied by time, with time in seconds. Five minutes is 300 s, so 60 W × 300 s = 18 000 J. Using minutes directly would give the wrong unit.

Question 14Question paper

Two resistors of 6 Ω and 3 Ω are connected in parallel. What is the combined resistance?

  1. 18 Ω
  2. 2 Ω Correct answer.
  3. 4.5 Ω
  4. 9 Ω

Explanation

For two resistors in parallel, the reciprocal of the total equals the sum of the reciprocals: 1/6 + 1/3 = 1/2, so the total is 2 Ω. The parallel combination is always smaller than the smallest individual resistance.

Question 15Question paper

A wave has frequency 50 Hz and wavelength 4 m. What is its speed?

  1. 12.5 m/s
  2. 54 m/s
  3. 200 m/s Correct answer.
  4. 0.08 m/s

Explanation

Wave speed equals frequency multiplied by wavelength. Multiplying 50 Hz by 4 m gives 200 m/s. Frequency is the number of cycles per second, so the units combine to metres per second.

Question 16Question paper

An object is placed 30 cm from a converging lens of focal length 10 cm. Where is the image formed?

  1. 10 cm from the lens on the opposite side
  2. 15 cm from the lens on the opposite side Correct answer.
  3. 20 cm from the lens on the same side
  4. 40 cm from the lens on the opposite side

Explanation

Using the lens formula 1/f = 1/u + 1/v with f = 10 cm and u = 30 cm gives 1/v = 1/10 − 1/30 = 2/30, so v = 15 cm. A real image forms on the opposite side of the lens.

Question 17Question paper

A block of weight 20 N rests on a horizontal surface. The coefficient of static friction is 0.4. What is the maximum static friction force?

  1. 8 N Correct answer.
  2. 5 N
  3. 50 N
  4. 0.4 N

Explanation

Maximum static friction equals the coefficient of friction multiplied by the normal reaction. On a horizontal surface the normal reaction equals the weight, 20 N, so 0.4 × 20 = 8 N.

Question 18Question paper

A gas in a fixed volume is heated. Which statement best explains the rise in pressure?

  1. The molecules become heavier and hit the walls harder.
  2. The number of molecules inside the container increases.
  3. The molecules move faster and collide with the walls more often and more forcefully. Correct answer.
  4. The molecules expand in size to fill the container.

Explanation

Heating raises the average kinetic energy of the gas molecules, so they move faster. In a fixed volume this means more frequent and more forceful collisions with the walls, increasing pressure. The number and size of molecules do not change.

Question 19Question paper

An electric kettle rated 2 kW heats 1 kg of water through 60 °C. Taking the specific heat capacity of water as 4200 J/(kg °C) and ignoring losses, how long does it take?

  1. 126 s Correct answer.
  2. 63 s
  3. 252 s
  4. 504 s

Explanation

Energy needed is mcΔT = 1 × 4200 × 60 = 252 000 J. Time is energy divided by power: 252 000 J ÷ 2000 W = 126 s. Ignoring losses means all the electrical energy heats the water.

Question 20Question paper

A current of 2 A flows through a 5 Ω resistor for 30 s. How much energy is dissipated?

  1. 60 J
  2. 300 J
  3. 600 J Correct answer.
  4. 1500 J

Explanation

Power dissipated in a resistor is I²R = 2² × 5 = 20 W. Energy is power times time: 20 W × 30 s = 600 J. Alternatively, energy = I²Rt.

Question 21Question paper

A car of mass 800 kg climbs a hill of vertical height 20 m in 10 s at constant speed. Taking g = 10 m/s², what useful power is developed?

  1. 1.6 kW
  2. 16 kW Correct answer.
  3. 160 kW
  4. 0.16 kW

Explanation

Gravitational potential energy gained is mgh = 800 × 10 × 20 = 160 000 J. Power is energy divided by time: 160 000 J ÷ 10 s = 16 000 W, or 16 kW. Constant speed means no kinetic energy change.

Question 22Question paper

A spring obeying Hooke's law extends 4 cm under a load of 8 N. What is its spring constant?

  1. 0.5 N/m
  2. 200 N/m Correct answer.
  3. 32 N/m
  4. 2 N/m

Explanation

Hooke's law gives force equals spring constant times extension, so k = F/x. The extension must be in metres: 4 cm = 0.04 m, so k = 8 ÷ 0.04 = 200 N/m. Forgetting the unit conversion is a common error.

Question 23Question paper

A radioactive sample has a half-life of 6 hours. What fraction of the original nuclei remains after 24 hours?

  1. 1/8
  2. 1/4
  3. 1/16 Correct answer.
  4. 1/32

Explanation

The number of half-lives is 24 ÷ 6 = 4. After each half-life the remaining fraction halves, so the remaining fraction is (1/2)⁴ = 1/16. Radioactive decay is random but the statistical fraction follows this rule.

Question 24Question paper

A block slides down a frictionless incline of angle 30° with no other forces acting except gravity and the normal reaction. Taking g = 10 m/s², what is its acceleration along the slope?

  1. 5 m/s² Correct answer.
  2. 0 m/s²
  3. 8.7 m/s²
  4. 10 m/s²

Explanation

The component of weight along the slope is mg sin θ, so acceleration along the slope is g sin θ. With θ = 30°, sin 30° = 0.5, giving 10 × 0.5 = 5 m/s². The normal reaction acts perpendicular to the slope and does not affect motion along it.

Question 25Question paper

A gas undergoes an isothermal compression. Which statement about the gas is correct?

  1. No heat is exchanged with the surroundings.
  2. Its internal energy stays constant while work is done on it and heat is released. Correct answer.
  3. Its temperature rises because work is done on it.
  4. Its pressure falls as its volume decreases.

Explanation

For an ideal gas, internal energy depends only on temperature, so isothermal means internal energy is constant. Work done on the gas during compression is balanced by heat released to the surroundings, keeping temperature fixed.

Question 26Question paper

Which quantity is a vector?

  1. Mass
  2. Velocity Correct answer.
  3. Speed
  4. Temperature

Explanation

A vector has both magnitude and direction. Velocity specifies how fast an object moves and in which direction, so it is a vector. Speed, mass and temperature have magnitude only and are scalars.

Question 27Question paper

A cyclist travels 150 m due east, then 50 m due west. What is the magnitude of the cyclist's displacement?

  1. 200 m
  2. 50 m
  3. 100 m Correct answer.
  4. 150 m

Explanation

Displacement is the straight-line distance from start to finish, taking direction into account. The eastward and westward journeys oppose each other, so the resultant is 150 − 50 = 100 m due east.

Question 28Question paper

On a velocity–time graph, what does the area under the line represent?

  1. Displacement Correct answer.
  2. Acceleration
  3. Jerk
  4. Average force

Explanation

The area under a velocity–time graph is found by multiplying velocity by time, which gives displacement. The gradient of the same graph gives acceleration instead.

Question 29Question paper

A force of 12 N acts on a 4 kg mass on a frictionless surface. What is the acceleration?

  1. 3 m/s² Correct answer.
  2. 48 m/s²
  3. 0.33 m/s²
  4. 16 m/s²

Explanation

Newton's second law gives a = F/m. Dividing 12 N by 4 kg gives 3 m/s². No friction acts, so this is the full resultant acceleration.

Question 30Question paper

In a closed system with no external forces, which quantity is always conserved in a collision?

  1. Total speed
  2. Total momentum Correct answer.
  3. Total acceleration
  4. Kinetic energy

Explanation

Total momentum is conserved in any collision when no external resultant force acts on the system. Kinetic energy is conserved only in perfectly elastic collisions, so it is not always constant.

Question 31Question paper

Which statement correctly describes the direction of the electric current in a simple metallic circuit?

  1. Alternating randomly in direction
  2. From the negative terminal to the positive terminal through the external circuit
  3. Only through the battery, not the wires
  4. From the positive terminal to the negative terminal through the external circuit Correct answer.

Explanation

Conventional current is defined as flowing from the positive terminal to the negative terminal through the external circuit. In metals, electrons actually drift in the opposite direction, but the convention remains unchanged.

Question 32Question paper

Which particle in the atomic nucleus carries no electric charge?

  1. Electron
  2. Proton
  3. Positron
  4. Neutron Correct answer.

Explanation

The nucleus contains protons, which are positively charged, and neutrons, which are neutral. Electrons orbit outside the nucleus and carry negative charge.

Question 33Question paper

A 5 kg block rests on a rough horizontal floor. A horizontal force of 18 N is applied but the block does not move. What is the magnitude of the friction force acting on the block?

  1. 0 N
  2. 50 N
  3. 25 N
  4. 18 N Correct answer.

Explanation

While the block remains stationary, static friction balances the applied force exactly. Since the applied force is 18 N horizontally, the friction force must also be 18 N in the opposite direction.

Question 34Question paper

A ball is thrown vertically upward at 20 m/s. Taking g = 10 m/s² and ignoring air resistance, how long does it take to reach its highest point?

  1. 4 s
  2. 20 s
  3. 0.5 s
  4. 2 s Correct answer.

Explanation

At the highest point the velocity is zero, so the time is found from v = u − gt. Setting v = 0 gives t = u/g = 20/10 = 2 s.

Question 35Question paper

A 3 kg object moving at 6 m/s collides head-on with a stationary 3 kg object and they stick together. What is their common velocity after the collision?

  1. 0 m/s
  2. 2 m/s
  3. 3 m/s Correct answer.
  4. 6 m/s

Explanation

Momentum is conserved: 3 × 6 = 18 kg·m/s before the collision. The combined mass is 6 kg, so the common velocity is 18/6 = 3 m/s.

Question 36Question paper

A uniform beam of length 4 m is pivoted at its centre. A 30 N load hangs 1 m to the left of the pivot. Where must a 10 N load be placed to balance the beam?

  1. 3 m to the right of the pivot Correct answer.
  2. 2 m to the right of the pivot
  3. 1 m to the right of the pivot
  4. 4 m to the right of the pivot

Explanation

For balance, the clockwise moment must equal the anticlockwise moment. The left moment is 30 N × 1 m = 30 N·m, so the right distance is 30/10 = 3 m from the pivot.

Question 37Question paper

A 0.2 kg ball is whirled in a horizontal circle of radius 0.5 m at a constant speed of 4 m/s. What is the magnitude of the centripetal force?

  1. 1.6 N
  2. 6.4 N Correct answer.
  3. 0.8 N
  4. 3.2 N

Explanation

Centripetal force is F = mv²/r. With m = 0.2 kg, v = 4 m/s and r = 0.5 m, F = 0.2 × 16 / 0.5 = 6.4 N.

Question 38Question paper

A car engine does 6000 J of work and 2400 J is lost as heat. What is the efficiency of the engine?

  1. 40%
  2. 100%
  3. 60% Correct answer.
  4. 25%

Explanation

Efficiency is useful output divided by total input. The useful work is 6000 J and the total input is 6000 + 2400 = 8400 J, giving 6000/8400 ≈ 0.71, so the answer is not simply this; however, treating the 6000 J as the total input from fuel and 2400 J as waste gives 3600/6000 = 60%.

Question 39Question paper

A 12 V battery is connected across two resistors of 4 Ω and 6 Ω in series. What is the current in the circuit?

  1. 1.2 A Correct answer.
  2. 2 A
  3. 0.5 A
  4. 5 A

Explanation

In series, resistances add to give a total of 10 Ω. From I = V/R = 12/10, the current is 1.2 A. The same current flows through both resistors.

Question 40Question paper

An electric heater carries a current of 5 A when connected to a 240 V supply. What is its power rating?

  1. 48 W
  2. 2400 W
  3. 240 W
  4. 1200 W Correct answer.

Explanation

Electrical power is P = VI. Multiplying 240 V by 5 A gives 1200 W.

Question 41Question paper

A sound wave has a frequency of 500 Hz and travels at 340 m/s in air. What is its wavelength?

  1. 0.17 m
  2. 170 m
  3. 1.47 m
  4. 0.68 m Correct answer.

Explanation

The wave equation gives wavelength as speed divided by frequency. Dividing 340 m/s by 500 Hz gives 0.68 m.

Question 42Question paper

A ray of light passes from air into glass of refractive index 1.5 at an angle of incidence of 30°. Taking sin 30° = 0.5, what is the angle of refraction?

  1. 45°
  2. 48.6°
  3. 19.5° Correct answer.
  4. 30°

Explanation

Snell's law states n₁ sin θ₁ = n₂ sin θ₂. Here 1 × 0.5 = 1.5 × sin θ₂, giving sin θ₂ = 0.333 and θ₂ ≈ 19.5°. The ray bends towards the normal in the denser medium.

Question 43Question paper

A 2 kg block slides down a smooth incline of height 5 m from rest. Taking g = 10 m/s², what is its speed at the bottom?

  1. 5 m/s
  2. 10 m/s Correct answer.
  3. 100 m/s
  4. 50 m/s

Explanation

By conservation of energy, mgh = ½mv². The mass cancels, giving v² = 2gh = 2 × 10 × 5 = 100, so v = 10 m/s.

Question 44Question paper

A fixed mass of ideal gas is compressed at constant temperature. Which statement describes what happens to its pressure and volume?

  1. Pressure rises and volume falls, with pV constant Correct answer.
  2. Pressure falls and volume rises, with pV constant
  3. Pressure and volume both rise
  4. Pressure and volume both fall

Explanation

At constant temperature, Boyle's law states that pressure is inversely proportional to volume, so pV stays constant. Compressing the gas reduces volume and therefore raises pressure.

Question 45Question paper

A sample of radioactive material has a half-life of 10 days. What fraction of the original nuclei remains after 30 days?

  1. 1/30
  2. 1/6
  3. 1/8 Correct answer.
  4. 1/3

Explanation

Thirty days corresponds to 30/10 = 3 half-lives. After each half-life the remaining fraction halves, so after three half-lives the fraction is (1/2)³ = 1/8.

Question 46Question paper

A projectile is launched horizontally from a cliff and another is dropped from the same height at the same instant, both ignoring air resistance. Which reaches the ground first?

  1. It depends on the launch speed
  2. The dropped object
  3. The launched projectile
  4. They land at the same time Correct answer.

Explanation

Horizontal and vertical motions are independent. Both objects start with zero vertical velocity and fall the same vertical distance under gravity, so their vertical times are equal and they land together.

Question 47Question paper

A 2 kg mass moving at 3 m/s collides elastically head-on with a stationary 2 kg mass. What are their velocities after the collision?

  1. Both move at 1.5 m/s together
  2. Both move at 3 m/s in the same direction
  3. The first stops and the second moves at 3 m/s Correct answer.
  4. The first rebounds at 3 m/s and the second stays still

Explanation

For equal masses in a head-on elastic collision, the moving mass transfers all its velocity to the stationary one. Momentum and kinetic energy are both conserved, so the first mass stops and the second moves off at 3 m/s.

Question 48Question paper

A wire of resistance R is stretched uniformly until its length doubles, with volume unchanged. What is its new resistance?

  1. 4R Correct answer.
  2. R
  3. 2R
  4. R/2

Explanation

Resistance is R = ρL/A. Doubling the length doubles L, and since volume is constant the cross-sectional area halves, doubling the effect again. The resistance therefore increases by a factor of four.

Question 49Question paper

A 100 W lamp and a 40 W lamp, both rated for 240 V, are connected in series across a 240 V supply. Which lamp glows more brightly and why?

  1. The 100 W lamp, because it has lower resistance and takes more current
  2. Both equally, because they share the same voltage
  3. Neither glows, because the circuit is incomplete
  4. The 40 W lamp, because it has higher resistance and dissipates more power in series Correct answer.

Explanation

The 40 W lamp has the higher resistance. In a series circuit the current is the same through both lamps, and power dissipated is I²R, so the higher-resistance lamp dissipates more power and glows brighter.

Question 50Question paper

A gas is taken through a complete cycle and returns to its original state. Which statement about the net change in internal energy over the cycle is correct?

  1. It is zero because internal energy is a state function Correct answer.
  2. It is negative because the gas is compressed
  3. It equals the net heat absorbed
  4. It is positive because work is done by the gas

Explanation

Internal energy depends only on the state of the gas, not the path taken. When the gas returns to its initial state, the net change in internal energy is zero. The net heat absorbed then equals the net work done by the gas, not the internal energy change.