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Question 1Physics

A body moves along a straight line with constant acceleration. Which quantity changes at a uniform rate with time?

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

Explanation

Constant acceleration means velocity changes by equal amounts in equal time intervals, so the velocity–time graph is a straight line. Displacement grows quadratically with time, and acceleration is by definition constant, so neither changes uniformly.

Question 2Physics

A stone is dropped from rest and falls freely near the Earth's surface. Taking g = 10 m/s², how far does it fall in the first 3 s?

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

Explanation

For free fall from rest, distance s = ½gt². Substituting gives ½ × 10 × 3² = 45 m. The value 30 m would only follow from using s = gt, which omits the factor of one half.

Question 3Physics

A force of 20 N acts on a 4 kg mass that is free to move on a frictionless surface. What is the acceleration produced?

  1. 5 m/s² Correct answer.
  2. 80 m/s²
  3. 24 m/s²
  4. 0.2 m/s²

Explanation

Newton's second law gives a = F/m. Dividing 20 N by 4 kg yields 5 m/s². The other values come from multiplying the quantities or adding them instead of dividing.

Question 4Physics

A body of weight 50 N rests on a horizontal table. What is the normal reaction force exerted by the table on the body?

  1. 100 N upward
  2. Zero
  3. 50 N downward
  4. 50 N upward Correct answer.

Explanation

Since the body is in vertical equilibrium, the upward normal reaction must balance the downward weight. The reaction is therefore 50 N directed upward. It is not a Newton's-third-law pair with the weight, because both forces act on the same body.

Question 5Physics

A pump raises 200 kg of water through a height of 10 m in 20 s. Taking g = 10 m/s², what is the useful power output?

  1. 20 000 W
  2. 1000 W Correct answer.
  3. 2000 W
  4. 200 W

Explanation

Useful power equals work done divided by time, and the work is mgh. That gives (200 × 10 × 10)/20 = 1000 W. Multiplying incorrectly or omitting the time division gives the other values.

Question 6Physics

A ball of mass 0.5 kg moving at 8 m/s is brought to rest in 0.2 s. What is the magnitude of the average force acting on it?

  1. 40 N
  2. 2 N
  3. 4 N
  4. 20 N Correct answer.

Explanation

The impulse–momentum theorem gives F = mΔv/Δt. The change in momentum is 0.5 × 8 = 4 kg·m/s, and dividing by 0.2 s gives 20 N. Simply multiplying mass by velocity gives the momentum, not the force.

Question 7Physics

Two bodies of masses 2 kg and 3 kg moving toward each other at 4 m/s and 2 m/s respectively collide and stick together. What is their common velocity after collision?

  1. 1.0 m/s in the direction of the 2 kg body
  2. 2.8 m/s in the direction of the 3 kg body
  3. 0.4 m/s in the direction of the 3 kg body
  4. 0.4 m/s in the direction of the 2 kg body Correct answer.

Explanation

Momentum is conserved: (2 × 4) − (3 × 2) = 8 − 6 = 2 kg·m/s, and the total mass is 5 kg. Dividing gives 0.4 m/s in the direction of the initially faster 2 kg body. The sign of the second momentum must be taken as negative because it moves oppositely.

Question 8Physics

A satellite orbits the Earth in a circular path. Which statement about the force on it is correct?

  1. The gravitational force does work on the satellite, increasing its kinetic energy.
  2. The gravitational force acts along the velocity, changing its speed.
  3. No force acts on the satellite because it is in orbit.
  4. The gravitational force acts perpendicular to the velocity and does no work. Correct answer.

Explanation

In a circular orbit the gravitational force points toward the centre, always perpendicular to the tangential velocity. Since force and displacement are perpendicular, the work done is zero and the speed stays constant. A force is still required to provide the centripetal acceleration.

Question 9Physics

A body of mass 2 kg is raised through 5 m and then allowed to fall back. Taking g = 10 m/s², what is its kinetic energy just before reaching the ground?

  1. 50 J
  2. 100 J Correct answer.
  3. 200 J
  4. 10 J

Explanation

By conservation of energy, the potential energy gained mgh is converted to kinetic energy on return. That gives 2 × 10 × 5 = 100 J. The other values come from using only one of the factors or misapplying the formula.

Question 10Physics

A block slides down a rough inclined plane at constant velocity. Which statement is correct?

  1. The net force on the block is zero. Correct answer.
  2. The frictional force is greater than the component of weight along the plane.
  3. The normal reaction equals the weight of the block.
  4. The block is accelerating because gravity acts on it.

Explanation

Constant velocity means zero acceleration, and by Newton's second law the net force must be zero. The component of weight down the plane is exactly balanced by kinetic friction, while the normal reaction balances only the perpendicular component of weight.

Question 11Physics

A car of mass 1000 kg rounds a circular bend of radius 50 m at 10 m/s. What is the centripetal force required?

  1. 20 000 N
  2. 200 N
  3. 500 N
  4. 2000 N Correct answer.

Explanation

Centripetal force is F = mv²/r. Substituting gives 1000 × 100 / 50 = 2000 N. The other values arise from dividing by the wrong quantity or squaring incorrectly.

Question 12Physics

A body weighs 60 N on the Earth's surface. Taking the value of g on the Moon as one-sixth of that on Earth, what is its weight on the Moon?

  1. 0 N
  2. 60 N
  3. 360 N
  4. 10 N Correct answer.

Explanation

Weight is mg, and the Moon's gravitational field is one-sixth of Earth's, so the weight is 60/6 = 10 N. The mass remains unchanged, but weight depends on the local field strength.

Question 13Physics

A simple pendulum has a period of 2 s on Earth. If taken to a place where the acceleration due to gravity is four times larger, what is its new period?

  1. 8 s
  2. 1 s Correct answer.
  3. 2 s
  4. 4 s

Explanation

The period of a simple pendulum is T = 2π√(L/g), so it varies inversely with the square root of g. Quadrupling g halves the period to 1 s. Only the length and the local field strength affect the period.

Question 14Physics

A wave travels at 180 m/s through a medium and has a frequency of 60 Hz. What is its wavelength in that medium?

  1. 120 m
  2. 0.33 m
  3. 3 m Correct answer.
  4. 10800 m

Explanation

Wave speed equals frequency times wavelength. Dividing 180 metres per second by 60 cycles per second gives a wavelength of 3 metres for each cycle.

Question 15Physics

Light passes from air into glass of refractive index 1.5. Which statement about the light in the glass is correct?

  1. Its speed increases and its wavelength increases.
  2. Its speed decreases and its frequency stays the same. Correct answer.
  3. Its speed decreases and its frequency decreases.
  4. Its frequency increases and its wavelength stays the same.

Explanation

When light enters a denser medium, its speed falls to v = c/n. The frequency is set by the source and does not change at the boundary, so the wavelength shortens. This is why refraction bends the ray toward the normal.

Question 16Physics

An object is placed between the pole and the principal focus of a concave mirror. What is the nature of the image formed?

  1. Virtual, erect and magnified Correct answer.
  2. Real, inverted and diminished
  3. Real, inverted and magnified
  4. Virtual, erect and diminished

Explanation

For an object inside the focal point of a concave mirror, the reflected rays diverge and form a virtual, erect, magnified image behind the mirror. This is the principle of the shaving mirror. Real images form only when the object lies beyond the focus.

Question 17Physics

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

  1. 4.5 Ω
  2. 9 Ω
  3. 0.5 Ω
  4. 2 Ω Correct answer.

Explanation

For parallel resistors, 1/R = 1/6 + 1/3 = 1/2, so R = 2 Ω. The equivalent resistance of a parallel combination is always smaller than the smallest individual resistance. Adding the values would apply only to a series connection.

Question 18Physics

A charge of 4 C flows through a conductor in 2 s. What is the current?

  1. 6 A
  2. 8 A
  3. 0.5 A
  4. 2 A Correct answer.

Explanation

Current is the rate of flow of charge, I = Q/t. Dividing 4 C by 2 s gives 2 A. The other options come from multiplying or adding the given values.

Question 19Physics

A wire of resistance 10 Ω carries a current of 2 A for 5 s. How much heat is produced?

  1. 200 J Correct answer.
  2. 100 J
  3. 400 J
  4. 20 J

Explanation

Joule heating is given by H = I²Rt. Substituting gives 4 × 10 × 5 = 200 J. The other values arise from omitting the square on the current or dropping one of the factors.

Question 20Physics

An electric heater rated 1000 W operates on a 250 V supply. What is the current drawn?

  1. 4 A Correct answer.
  2. 0.25 A
  3. 250 000 A
  4. 1250 A

Explanation

Electrical power is P = VI, so I = P/V. Dividing 1000 W by 250 V gives 4 A. The resistance of the element would then be V/I = 62.5 Ω, but that is not asked.

Question 21Physics

A charged particle enters a uniform magnetic field with its velocity parallel to the field lines. What path does it follow?

  1. A helical path around the field lines
  2. A parabolic path like a projectile
  3. A straight line with unchanged speed Correct answer.
  4. A circular path in the plane perpendicular to the field

Explanation

The magnetic force on a moving charge is F = qvB sinθ, where θ is the angle between velocity and field. When the velocity is parallel, sinθ = 0, so no force acts and the particle moves in a straight line at constant speed. Circular or helical motion needs a velocity component perpendicular to the field.

Question 22Physics

A transformer has 500 turns in the primary and 50 turns in the secondary. If the primary is connected to a 220 V supply, what is the secondary voltage?

  1. 22 V Correct answer.
  2. 440 V
  3. 2200 V
  4. 110 V

Explanation

For an ideal transformer, Vs/Vp = Ns/Np. The turns ratio is 50/500 = 0.1, so the secondary voltage is 0.1 × 220 = 22 V. This is a step-down transformer because the secondary has fewer turns.

Question 23Physics

In the photoelectric effect, the maximum kinetic energy of emitted electrons depends on which property of the incident light?

  1. Its wavelength only, independent of intensity
  2. Its speed of propagation
  3. Its intensity only
  4. Its frequency, with intensity affecting only the number of electrons Correct answer.

Explanation

Einstein's photoelectric equation is Kmax = hf − φ, so the maximum kinetic energy rises linearly with frequency above the threshold. Intensity controls the number of photons and hence the photocurrent, not the energy per electron. The work function φ is a property of the metal.

Question 24Physics

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

  1. One quarter
  2. One half
  3. One eighth Correct answer.
  4. One sixteenth

Explanation

Thirty days is three half-lives, since 30/10 = 3. Each half-life halves the remaining nuclei, so the fraction is (1/2)³ = 1/8. This is exponential decay, not a linear decrease.

Question 25Physics

In a nuclear fission reaction, a small amount of mass appears to be missing from the products. What happens to this mass?

  1. It escapes as a neutron without energy.
  2. It is stored in the nucleus as extra charge.
  3. It is destroyed because mass is not conserved in any reaction.
  4. It is converted into energy according to E = mc². Correct answer.

Explanation

The missing mass, called the mass defect, is released as energy given by E = mc². This is the source of the large energy output of fission reactors. Mass–energy as a whole is conserved; the mass does not simply vanish.

Question 26Physics

A body moves 4 m east, then 3 m north. What is the magnitude of its displacement?

  1. 1 m
  2. 5 m Correct answer.
  3. 3.5 m
  4. 7 m

Explanation

Displacement is the straight-line distance from start to finish. The two legs are perpendicular, so by Pythagoras the magnitude is √(4² + 3²) = 5 m.

Question 27Physics

A car accelerates uniformly from rest to 20 m/s in 5 s. What is its acceleration?

  1. 20 m/s²
  2. 4 m/s² Correct answer.
  3. 100 m/s²
  4. 0.25 m/s²

Explanation

Acceleration is the change in velocity divided by the time taken. Here a = (20 − 0)/5 = 4 m/s².

Question 28Physics

A force of 10 N acts on a body and displaces it by 2 m in the direction of the force. What is the work done?

  1. 5 J
  2. 12 J
  3. 0 J
  4. 20 J Correct answer.

Explanation

Work done by a constant force along the displacement is W = F s cos θ. With θ = 0°, W = 10 × 2 = 20 J.

Question 29Physics

Two masses, 2 kg and 4 kg, are separated by a centre-to-centre distance of 3 m. Taking G = 6.67 × 10⁻¹¹ N m² kg⁻², what is the gravitational force between them?

  1. 1.78 × 10⁻¹⁰ N
  2. 2.67 × 10⁻¹⁰ N
  3. 8.89 × 10⁻¹¹ N
  4. 5.93 × 10⁻¹¹ N Correct answer.

Explanation

Newton's law of gravitation gives F = G m₁ m₂ / r². Substituting gives F = (6.67 × 10⁻¹¹ × 2 × 4) / 3² = 5.93 × 10⁻¹¹ N.

Question 30Physics

A solid sphere and a solid cylinder, both of the same mass and radius, are released from rest at the top of the same inclined plane and roll without slipping. Which reaches the bottom first?

  1. Both reach together
  2. The sphere Correct answer.
  3. The cylinder
  4. It depends on the angle of the incline

Explanation

For rolling without slipping, acceleration down an incline is a = g sinθ / (1 + I/(MR²)). The sphere has the smaller moment of inertia factor (2/5) compared with the cylinder (1/2), so it has the greater acceleration and arrives first.

Question 31Physics

A body of mass 2 kg moving at 3 m/s collides head-on with a stationary body of mass 1 kg. If the collision is perfectly elastic, what is the velocity of the 2 kg body immediately after the collision?

  1. 1 m/s in the original direction Correct answer.
  2. 3 m/s in the original direction
  3. 0 m/s
  4. 2 m/s in the opposite direction

Explanation

For a perfectly elastic head-on collision, v₁' = ((m₁ − m₂)/(m₁ + m₂))u₁. Here v₁' = ((2 − 1)/3) × 3 = 1 m/s, still in the original direction.

Question 32Physics

A body of mass 0.5 kg is attached to a string and whirled in a vertical circle of radius 1 m. At the lowest point its speed is 5 m/s. Taking g = 10 m/s², what is the tension in the string at that point?

  1. 7.5 N
  2. 12.5 N
  3. 2.5 N
  4. 17.5 N Correct answer.

Explanation

At the lowest point the tension acts upward and weight downward, so T − mg = mv²/r. Thus T = mg + mv²/r = 5 + (0.5 × 25)/1 = 17.5 N.

Question 33Physics

A block of mass 2 kg is pulled along a rough horizontal surface by a horizontal force of 10 N. The coefficient of kinetic friction is 0.2 and g = 10 m/s². What is the acceleration of the block?

  1. 1 m/s²
  2. 7 m/s²
  3. 5 m/s²
  4. 3 m/s² Correct answer.

Explanation

The kinetic friction force is f = μmg = 0.2 × 2 × 10 = 4 N. The net force is 10 − 4 = 6 N, so a = F_net/m = 6/2 = 3 m/s².

Question 34Physics

A body of mass 2 kg is tied to a string of length 1 m and moved in a horizontal circle at 4 m/s. What is the tension in the string?

  1. 32 N Correct answer.
  2. 16 N
  3. 64 N
  4. 8 N

Explanation

For circular motion the centripetal force is provided by the tension: T = mv²/r = (2 × 16)/1 = 32 N.

Question 35Physics

A particle executing simple harmonic motion has an amplitude of 5 cm and a period of 2 s. What is its maximum speed?

  1. 5π cm/s Correct answer.
  2. 10π cm/s
  3. 2.5π cm/s
  4. 5/π cm/s

Explanation

For SHM the maximum speed is v_max = ωA, where ω = 2π/T. Here ω = π rad/s, so v_max = π × 5 = 5π cm/s.

Question 36Physics

A spring of force constant 200 N/m is stretched by 10 cm from its natural length. What is the elastic potential energy stored?

  1. 20 J
  2. 0.1 J
  3. 1 J Correct answer.
  4. 2 J

Explanation

Elastic potential energy is U = ½kx². Converting 10 cm to 0.1 m gives U = ½ × 200 × (0.1)² = 1 J.

Question 37Physics

Water flows through a horizontal pipe that narrows from a cross-sectional area of 0.04 m² to 0.01 m². If the speed in the wider section is 2 m/s, what is the speed in the narrower section?

  1. 2 m/s
  2. 8 m/s Correct answer.
  3. 0.5 m/s
  4. 4 m/s

Explanation

The equation of continuity for an incompressible fluid gives A₁v₁ = A₂v₂. Thus v₂ = (0.04 × 2)/0.01 = 8 m/s.

Question 38Physics

A body floats with 40% of its volume above the surface of a liquid. What is the density of the body relative to the liquid?

  1. 0.6 Correct answer.
  2. 1.4
  3. 0.4
  4. 0.8

Explanation

For a floating body, the fraction submerged equals the ratio of the body's density to the liquid's density. Since 60% is submerged, the relative density is 0.6.

Question 39Physics

The temperature of a fixed mass of ideal gas is doubled at constant volume. What happens to its pressure?

  1. It becomes four times as large.
  2. It doubles. Correct answer.
  3. It halves.
  4. It remains the same.

Explanation

At constant volume, pressure is directly proportional to absolute temperature (P/T = constant). Doubling the absolute temperature therefore doubles the pressure.

Question 40Physics

A Carnot engine operates between a source at 500 K and a sink at 300 K. What is its efficiency?

  1. 40% Correct answer.
  2. 60%
  3. 20%
  4. 80%

Explanation

The Carnot efficiency is η = 1 − T_c/T_h, with temperatures in kelvin. Here η = 1 − 300/500 = 0.40, or 40%.

Question 41Physics

A metal rod of length 1 m is heated through 100 °C. If its coefficient of linear expansion is 1.2 × 10⁻⁵ K⁻¹, what is its increase in length?

  1. 1.2 × 10⁻⁴ m
  2. 1.2 × 10⁻⁵ m
  3. 1.2 × 10⁻³ m Correct answer.
  4. 1.2 × 10⁻² m

Explanation

Linear expansion is ΔL = αL₀ΔT. Substituting gives ΔL = 1.2 × 10⁻⁵ × 1 × 100 = 1.2 × 10⁻³ m.

Question 42Physics

In a stationary wave on a stretched string fixed at both ends, what is the phase difference between two points on opposite sides of a node?

  1. π radians Correct answer.
  2. 0 radians
  3. 2π radians
  4. π/2 radians

Explanation

In a stationary wave, all points between two adjacent nodes vibrate in phase, while points on opposite sides of a node vibrate in antiphase, a phase difference of π radians.

Question 43Physics

A source of sound moves toward a stationary observer. Compared with the emitted frequency, the observed frequency is

  1. zero
  2. lower
  3. higher Correct answer.
  4. the same

Explanation

The Doppler effect for a moving source gives f' = f v/(v − v_s) when the source approaches. Since the denominator is smaller than v, the observed frequency is higher than the emitted frequency.

Question 44Physics

Light of wavelength 600 nm in air enters a medium of refractive index 1.5. What is its wavelength in the medium?

  1. 300 nm
  2. 400 nm Correct answer.
  3. 900 nm
  4. 600 nm

Explanation

The frequency stays constant on refraction, and the speed and wavelength both reduce by the refractive index. Thus λ_medium = λ_air/n = 600/1.5 = 400 nm.

Question 45Physics

In a Young's double-slit experiment, the separation between adjacent bright fringes is 2 mm. If the distance from the slits to the screen is doubled while the slit separation and wavelength are unchanged, what is the new fringe separation?

  1. 2 mm
  2. 1 mm
  3. 4 mm Correct answer.
  4. 8 mm

Explanation

Fringe separation is β = λD/d, so it is directly proportional to the screen distance D. Doubling D therefore doubles β to 4 mm.

Question 46Physics

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

  1. 30 cm on the other side of the lens
  2. 20 cm on the same side as the object
  3. 15 cm on the other side of the lens Correct answer.
  4. 15 cm on the same side as the object

Explanation

Using the lens formula 1/f = 1/v − 1/u with u = −30 cm and f = +10 cm gives 1/v = 1/10 − 1/30 = 1/15, so v = +15 cm. The positive sign means a real image on the opposite side.

Question 47Physics

Three identical resistors, each of resistance R, are connected in parallel. What is the equivalent resistance of the combination?

  1. 3R
  2. R/3 Correct answer.
  3. R/9
  4. R

Explanation

For n identical resistors in parallel, the equivalent resistance is R/n. With three resistors the equivalent resistance is R/3.

Question 48Physics

A cell of emf 2 V and internal resistance 0.5 Ω is connected to an external resistance of 1.5 Ω. What is the terminal potential difference across the cell?

  1. 2.0 V
  2. 1.0 V
  3. 1.5 V Correct answer.
  4. 0.5 V

Explanation

The current is I = ε/(R + r) = 2/(1.5 + 0.5) = 1 A. The terminal potential difference is V = ε − Ir = 2 − (1 × 0.5) = 1.5 V.

Question 49Physics

A charged particle moves in a circular path of radius r in a uniform magnetic field B. If its speed is doubled while B is unchanged, what happens to the radius of its path?

  1. It remains the same.
  2. It halves.
  3. It doubles. Correct answer.
  4. It becomes four times as large.

Explanation

The magnetic force provides the centripetal force: qvB = mv²/r, so r = mv/(qB). The radius is directly proportional to speed, so doubling the speed doubles the radius.

Question 50Physics

An alternating current has a peak value of 10 A. What is its root-mean-square value?

  1. 7.07 A Correct answer.
  2. 10 A
  3. 5 A
  4. 14.14 A

Explanation

For a sinusoidal alternating current, the rms value is I_peak/√2. Thus I_rms = 10/1.414 ≈ 7.07 A.