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Question 1Physics

Which of the following is a vector quantity?

  1. Displacement Correct answer.
  2. Time
  3. Mass
  4. Speed

Explanation

A vector quantity has both magnitude and direction. Displacement specifies how far and in what direction, whereas speed, mass, and time are scalars with magnitude only.

Question 2Physics

A car accelerates uniformly from rest to 20 m/s in 5.0 s. What is its acceleration?

  1. 10 m/s²
  2. 2.0 m/s²
  3. 5.0 m/s²
  4. 4.0 m/s² Correct answer.

Explanation

Acceleration is the change in velocity divided by the time interval: a = (v - u)/t. Here u = 0, v = 20 m/s, and t = 5.0 s, so a = 20/5.0 = 4.0 m/s².

Question 3Physics

Newton's third law of motion states that:

  1. An object at rest stays at rest unless acted on by a force.
  2. The total momentum of an isolated system is conserved.
  3. For every action there is an equal and opposite reaction. Correct answer.
  4. Force equals mass times acceleration.

Explanation

Newton's third law describes action–reaction pairs: forces always occur in pairs of equal magnitude and opposite direction acting on different bodies. The other statements correspond to the first law, second law, and conservation of momentum, respectively.

Question 4Physics

Two resistors of 4 Ω and 6 Ω are connected in series. What is their equivalent resistance?

  1. 2.4 Ω
  2. 24 Ω
  3. 10 Ω Correct answer.
  4. 5.0 Ω

Explanation

In a series circuit, resistances add directly: R_eq = R1 + R2. Thus 4 Ω + 6 Ω = 10 Ω.

Question 5Physics

The SI unit of electric charge is the:

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

Explanation

Electric charge is measured in coulombs (C). One coulomb is the charge transported by a current of one ampere in one second.

Question 6Physics

Which of the following electromagnetic waves has the longest wavelength?

  1. Visible light
  2. Microwaves
  3. Radio waves Correct answer.
  4. Gamma rays

Explanation

In the electromagnetic spectrum, wavelength increases from gamma rays through X-rays, ultraviolet, visible, infrared, microwaves, to radio waves. Radio waves have the longest wavelengths.

Question 7Physics

The work done in lifting a 10 kg mass vertically through 2.0 m at constant speed is: (take g = 9.8 m/s²)

  1. 490 J
  2. 20 J
  3. 196 J Correct answer.
  4. 98 J

Explanation

Work done against gravity equals the change in gravitational potential energy: W = mgh. Thus W = 10 × 9.8 × 2.0 = 196 J.

Question 8Physics

The period of a simple pendulum depends on which of the following?

  1. The mass of the bob
  2. The amplitude for large swings
  3. The length of the pendulum Correct answer.
  4. The material of the string

Explanation

For small oscillations, the period of a simple pendulum is T = 2π√(L/g), which depends only on the length L and the acceleration due to gravity g. It is independent of the mass of the bob and, for small angles, of the amplitude.

Question 9Physics

A block of mass 2.0 kg rests on a rough horizontal surface. A horizontal force of 10 N is applied, but the block remains stationary. What is the magnitude of the static friction force acting on the block?

  1. 10 N Correct answer.
  2. 20 N
  3. 0 N
  4. 5.0 N

Explanation

Since the block remains at rest, the net horizontal force must be zero. Therefore the static friction force must exactly balance the applied force, giving 10 N.

Question 10Physics

A projectile is launched at an angle of 30° above the horizontal with a speed of 20 m/s. What is the horizontal component of its initial velocity? (cos30° ≈ 0.866, sin30° = 0.5)

  1. 34.6 m/s
  2. 20 m/s
  3. 10 m/s
  4. 17.3 m/s Correct answer.

Explanation

The horizontal component is v_x = v cosθ = 20 × cos30° ≈ 20 × 0.866 = 17.3 m/s.

Question 11Physics

A satellite orbits Earth in a circular orbit. If the radius of the orbit is doubled while the mass of the satellite remains the same, the gravitational force on the satellite becomes:

  1. One quarter as large Correct answer.
  2. Four times as large
  3. Twice as large
  4. Half as large

Explanation

According to Newton's law of gravitation, F = GMm/r². Doubling r increases the denominator by a factor of four, so the force becomes one quarter of its original value.

Question 12Physics

A force of 10 N acts on a body and displaces it by 3.0 m in a direction making 60° with the force. What is the work done by the force? (cos60° = 0.5)

  1. 26 J
  2. 0 J
  3. 30 J
  4. 15 J Correct answer.

Explanation

Work is the dot product of force and displacement: W = F d cosθ = 10 × 3.0 × 0.5 = 15 J.

Question 13Physics

A body of mass 2.0 kg moving at 3.0 m/s collides head-on with a stationary body of mass 1.0 kg. If they stick together, what is their common velocity after the collision?

  1. 1.0 m/s
  2. 3.0 m/s
  3. 2.0 m/s Correct answer.
  4. 1.5 m/s

Explanation

By conservation of momentum, m1u1 + m2u2 = (m1+m2)v. Thus 2.0×3.0 + 0 = (2.0+1.0)v, giving v = 6.0/3.0 = 2.0 m/s.

Question 14Physics

A wheel initially rotating at 10 rad/s accelerates uniformly at 2.0 rad/s². What angle does it turn through in 3.0 s?

  1. 30 rad
  2. 39 rad Correct answer.
  3. 60 rad
  4. 45 rad

Explanation

Using θ = ω₀t + ½αt², we get θ = 10×3.0 + 0.5×2.0×9.0 = 30 + 9 = 39 rad.

Question 15Physics

A simple pendulum has a period of 2.0 s on Earth. What would be its period on a planet where the acceleration due to gravity is four times that on Earth?

  1. 0.5 s
  2. 1.0 s Correct answer.
  3. 2.0 s
  4. 4.0 s

Explanation

The period of a simple pendulum is T = 2π√(L/g), so T is inversely proportional to √g. If g becomes 4g, T becomes T/√4 = T/2 = 1.0 s.

Question 16Physics

A wave has a frequency of 50 Hz and a wavelength of 4.0 m. What is its speed?

  1. 54 m/s
  2. 12.5 m/s
  3. 400 m/s
  4. 200 m/s Correct answer.

Explanation

Wave speed is the product of frequency and wavelength: v = fλ = 50 × 4.0 = 200 m/s.

Question 17Physics

Two point charges are separated by a distance r. If the distance between them is halved, the electrostatic force between them becomes:

  1. One quarter as large
  2. Four times as large Correct answer.
  3. Twice as large
  4. Half as large

Explanation

Coulomb's law states that F ∝ 1/r². Halving r makes the denominator (r/2)² = r²/4, so the force increases by a factor of four.

Question 18Physics

A 12 V battery is connected across a 4.0 Ω resistor. What is the power dissipated in the resistor?

  1. 36 W Correct answer.
  2. 3.0 W
  3. 48 W
  4. 144 W

Explanation

Power can be calculated as P = V²/R = (12)²/4.0 = 144/4.0 = 36 W.

Question 19Physics

A charged particle moves with velocity v perpendicular to a uniform magnetic field B. The path of the particle is:

  1. A straight line
  2. A parabola
  3. A circle Correct answer.
  4. A helix

Explanation

The magnetic force F = qv×B is always perpendicular to the velocity, so it provides a centripetal force of constant magnitude. This causes the particle to move in a circular path when v is perpendicular to B.

Question 20Physics

In a step-down transformer, the primary coil has 200 turns and the secondary coil has 50 turns. If the primary voltage is 240 V, what is the secondary voltage?

  1. 60 V Correct answer.
  2. 120 V
  3. 30 V
  4. 960 V

Explanation

For an ideal transformer, V_s/V_p = N_s/N_p. Thus V_s = 240 × (50/200) = 60 V.

Question 21Physics

The photoelectric effect provides evidence for which property of light?

  1. Interference
  2. Wave nature
  3. Polarization
  4. Particle nature Correct answer.

Explanation

The photoelectric effect shows that light delivers energy in discrete packets called photons, supporting the particle nature of light. The energy of emitted electrons depends on frequency, not intensity, which is consistent with photon theory.

Question 22Physics

A body of mass 0.50 kg is attached to a spring of spring constant 200 N/m and executes simple harmonic motion. What is the angular frequency of the motion?

  1. 10 rad/s
  2. 20 rad/s Correct answer.
  3. 400 rad/s
  4. 40 rad/s

Explanation

The angular frequency for a mass–spring system is ω = √(k/m) = √(200/0.50) = √400 = 20 rad/s.

Question 23Physics

An ideal gas undergoes an isothermal expansion. Which statement about the gas is correct?

  1. No heat is exchanged with the surroundings.
  2. The temperature of the gas increases.
  3. The heat absorbed by the gas equals the work done by the gas. Correct answer.
  4. The internal energy of the gas increases.

Explanation

For an isothermal process, the temperature remains constant, so the change in internal energy is zero. By the first law of thermodynamics, Q = ΔU + W, hence Q = W: the heat absorbed equals the work done by the gas.

Question 24Physics

A uniform meter stick of mass 0.20 kg is pivoted at its center. A 0.10 kg mass is hung 30 cm from the pivot on one side. At what distance from the pivot on the other side must a 0.15 kg mass be hung to balance the stick?

  1. 10 cm
  2. 45 cm
  3. 20 cm Correct answer.
  4. 30 cm

Explanation

For rotational equilibrium, the torques must balance: m1 g d1 = m2 g d2. Thus 0.10 × 30 = 0.15 × d2, giving d2 = 3.0/0.15 = 20 cm.

Question 25Physics

A convex lens of focal length 10 cm forms a real image of an object placed 15 cm from the lens. What is the image distance?

  1. 60 cm
  2. 15 cm
  3. 6.0 cm
  4. 30 cm Correct answer.

Explanation

Using the lens formula 1/f = 1/v - 1/u with u = -15 cm and f = +10 cm gives 1/v = 1/10 + 1/(-15) = 1/30, so v = 30 cm.

Question 26Physics

Which SI unit is equivalent to the newton per coulomb?

  1. joule per coulomb
  2. ampere per metre
  3. coulomb per second
  4. volt per metre Correct answer.

Explanation

Electric field strength E is force per unit charge, giving N/C, and also equals potential gradient, giving V/m. The two units describe the same quantity.

Question 27Physics

A body moves in a straight line at constant velocity. Which statement about the forces acting on it must be true?

  1. The net force acts opposite to the motion.
  2. A single constant force acts in the direction of motion.
  3. The net force increases with time.
  4. The net force is zero. Correct answer.

Explanation

Newton's first law states that constant velocity means zero acceleration, and by the second law zero acceleration requires zero net force. Individual forces may exist but must cancel.

Question 28Physics

The density of a material is defined as which ratio?

  1. force divided by area
  2. volume divided by mass
  3. mass divided by volume Correct answer.
  4. weight divided by volume

Explanation

Density is the mass per unit volume of a substance, expressed in kg/m³. Weight per unit volume is a different quantity (specific weight).

Question 29Physics

Which of the following is a scalar quantity?

  1. displacement
  2. momentum
  3. kinetic energy Correct answer.
  4. torque

Explanation

Scalars are fully described by magnitude alone; kinetic energy has no direction. Displacement, momentum and torque all require direction for a complete description.

Question 30Physics

A car travels 150 m in 10 s. Its average speed is:

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

Explanation

Average speed equals total distance divided by total time, so 150 m ÷ 10 s = 15 m/s.

Question 31Physics

A wire of resistance 6.0 Ω is cut into three equal lengths, and the pieces are connected in parallel. What is the resistance of the combination?

  1. 18 Ω
  2. 0.67 Ω Correct answer.
  3. 6.0 Ω
  4. 2.0 Ω

Explanation

Each third has resistance 2.0 Ω. Three 2.0 Ω resistors in parallel give 1/R = 3/2.0, so R = 0.67 Ω.

Question 32Physics

A block slides down a frictionless incline of height 1.8 m starting from rest. Its speed at the bottom is about:

  1. 18 m/s
  2. 1.8 m/s
  3. 5.9 m/s Correct answer.
  4. 3.0 m/s

Explanation

With no friction, potential energy converts fully to kinetic energy, so v = √(2gh) = √(2 × 9.8 × 1.8) ≈ 5.9 m/s. The incline angle does not affect the result.

Question 33Physics

Two identical resistors are connected in series across a battery of negligible internal resistance. Compared with connecting the same two resistors in parallel across the same battery, the series arrangement dissipates:

  1. four times the power
  2. half of the power
  3. twice the power
  4. one quarter of the power Correct answer.

Explanation

Series resistance is 2R and parallel resistance is R/2, a factor of four difference. Since P = V²/R_eq at fixed voltage, the series combination dissipates one quarter of the power.

Question 34Physics

A sound source moves toward a stationary observer. Compared with the emitted sound, the observed sound has:

  1. a higher frequency and a longer wavelength
  2. a lower frequency and a shorter wavelength
  3. the same frequency and a shorter wavelength
  4. a higher frequency and a shorter wavelength Correct answer.

Explanation

Approach compresses successive wavefronts, reducing the observed wavelength. Because wave speed in air is fixed, the reduced wavelength corresponds to a higher observed frequency.

Question 35Physics

An object is placed between a converging lens and its principal focus. The image formed is:

  1. virtual, upright and magnified Correct answer.
  2. real, inverted and magnified
  3. real, inverted and diminished
  4. virtual, inverted and diminished

Explanation

For an object inside the focal length of a converging lens, the rays diverge after refraction and appear to come from a virtual image on the same side. This image is upright and magnified, as in a magnifying glass.

Question 36Physics

A gas is compressed at constant temperature. Which statement about the molecules is correct?

  1. Their mean kinetic energy decreases because the volume falls.
  2. Their mean kinetic energy is unchanged, but they collide with the walls more often. Correct answer.
  3. Their mean kinetic energy is unchanged, and the collision frequency is unchanged.
  4. Their mean kinetic energy increases because the pressure rises.

Explanation

Mean kinetic energy of gas molecules depends only on absolute temperature, so it stays constant in an isothermal process. Reducing the volume raises the number density, so collisions with the walls occur more frequently and pressure rises.

Question 37Physics

A radioactive nuclide has a half-life of 8.0 days. What fraction of an initial sample remains undecayed after 24 days?

  1. 1/24
  2. 1/8 Correct answer.
  3. 1/4
  4. 1/3

Explanation

24 days is three half-lives. Each half-life halves the remaining amount, so the fraction left is (1/2)³ = 1/8.

Question 38Physics

In a nuclear fission reaction, a small amount of mass disappears. This mass appears as:

  1. a decrease in the total number of nucleons
  2. energy, according to E = mc² Correct answer.
  3. an increase in the charge of the nucleus
  4. extra neutrons only

Explanation

The mass defect is converted to energy according to Einstein's mass-energy relation E = mc². This released energy appears mainly as kinetic energy of the fission fragments.

Question 39Physics

A body is projected horizontally from a height of 20 m with a speed of 15 m/s. Taking g = 10 m/s², how far horizontally does it travel before landing?

  1. 15 m
  2. 20 m
  3. 30 m Correct answer.
  4. 45 m

Explanation

Vertical fall time from rest is t = √(2h/g) = √(2 × 20/10) = 2.0 s. Horizontal distance is then 15 × 2.0 = 30 m.

Question 40Physics

A uniform rod of length 2.0 m is pivoted at one end and held horizontally. Its weight is 30 N and acts at its midpoint. The torque about the pivot is:

  1. 15 N·m
  2. 0 N·m
  3. 30 N·m Correct answer.
  4. 60 N·m

Explanation

For a uniform rod the weight acts at the centre, 1.0 m from the pivot. Torque is force times perpendicular distance, 30 N × 1.0 m = 30 N·m.

Question 41Physics

A body of mass 4.0 kg moving at 5.0 m/s collides with and sticks to a stationary body of mass 6.0 kg. The kinetic energy lost in the collision is:

  1. 50 J
  2. 20 J
  3. 10 J
  4. 30 J Correct answer.

Explanation

Momentum conservation gives v = (4.0 × 5.0)/10 = 2.0 m/s. Initial kinetic energy is 50 J and final is 20 J, so 30 J is lost.

Question 42Physics

A particle moves in a circle of radius 0.50 m at a constant speed of 4.0 m/s. Its centripetal acceleration is:

  1. 32 m/s² Correct answer.
  2. 2.0 m/s²
  3. 16 m/s²
  4. 8.0 m/s²

Explanation

Centripetal acceleration is v²/r = (4.0)²/0.50 = 16/0.50 = 32 m/s². It points toward the centre of the circle.

Question 43Physics

An ideal gas at constant volume is heated so that its absolute temperature doubles. Its pressure:

  1. quadruples
  2. halves
  3. remains unchanged
  4. doubles Correct answer.

Explanation

Gay-Lussac's law states that at constant volume, pressure is directly proportional to absolute temperature. Doubling the absolute temperature therefore doubles the pressure.

Question 44Physics

A capacitor of 10 μF is charged to a potential difference of 100 V. The energy stored is:

  1. 0.050 J Correct answer.
  2. 0.010 J
  3. 1.0 J
  4. 0.50 J

Explanation

Energy stored is ½CV² = ½ × 10 × 10⁻⁶ × (100)² = 0.050 J. The factor of one half is essential in the capacitor energy formula.

Question 45Physics

Which phenomenon demonstrates that electrons behave as waves?

  1. Deflection of an electron beam by a magnetic field
  2. Thermionic emission
  3. The photoelectric effect
  4. Electron diffraction through a thin crystal Correct answer.

Explanation

Diffraction is a wave phenomenon, and electron diffraction patterns confirm the de Broglie wavelength of electrons. The other listed effects are explained by particle behaviour.

Question 46Physics

A projectile is launched from level ground and returns to the same level. At the highest point of its path:

  1. the acceleration is zero
  2. the vertical velocity is zero while the horizontal velocity is unchanged Correct answer.
  3. both velocity components are zero
  4. the horizontal velocity is zero while the vertical velocity is maximum

Explanation

At the apex the vertical component of velocity has been reduced to zero by gravity, while the horizontal component remains constant because no horizontal force acts. The acceleration is still g downward.

Question 47Physics

A block rests on the floor of a lift that accelerates upward. Compared with when the lift is at rest, the normal force on the block:

  1. increases Correct answer.
  2. stays the same
  3. becomes zero
  4. decreases

Explanation

The net upward force must equal ma, so N − mg = ma, giving N = m(g + a). The normal force therefore exceeds the weight when the lift accelerates upward.

Question 48Physics

Two identical waves travelling in opposite directions in the same medium superpose. At a point where the phase difference is 180°, the resultant displacement is:

  1. indefinite and varying with time
  2. zero, and the point is a node Correct answer.
  3. twice the amplitude of one wave
  4. equal to the amplitude of one wave

Explanation

When two equal-amplitude waves meet exactly out of phase, their displacements cancel at all times at that point. Such a point of permanent zero displacement is a node of the standing wave.

Question 49Physics

A charged particle enters a region containing crossed uniform electric and magnetic fields with no deflection. If the electric field strength is E and the magnetic flux density is B, the particle's speed is:

  1. E/B Correct answer.
  2. EB
  3. E/B²
  4. B/E

Explanation

Zero deflection requires the electric force qE to balance the magnetic force qvB. Equating them gives v = E/B, the basis of the velocity selector.

Question 50Physics

A step-up transformer is used to transmit electrical power along a cable of fixed resistance. Raising the transmission voltage reduces the power lost in the cable because:

  1. the electrons travel faster through the cable
  2. the current is reduced for the same power, and loss depends on current squared Correct answer.
  3. the power transmitted increases
  4. the resistance of the cable decreases

Explanation

For a given power P = VI, raising the voltage lowers the current. Cable loss is I²R, so reducing the current greatly reduces the loss even though the resistance is unchanged.