Physics Study Resources for Competitive Exam Success

Physics

Electricity & Magnetism Force & Energy Heat & Thermodynamics Modern Physics Basics Motion Optics Sound

Q. If a car does 3000 J of work in moving a distance of 150 m, what is the average force exerted by the car? (2023)

A. 20 N
B. 30 N
C. 40 N
D. 50 N

Solution

Average Force = Work / Distance = 3000 J / 150 m = 20 N

Correct Answer: B — 30 N

Learn More →

Q. If a car does 600 J of work in moving a distance of 30 m, what is the average force exerted by the car? (2023)

A. 20 N
B. 15 N
C. 25 N
D. 10 N

Solution

Average Force (F) = Work (W) / Distance (d) = 600 J / 30 m = 20 N.

Correct Answer: A — 20 N

Learn More →

Q. If a car does 6000 J of work in moving a distance of 100 m, what is the average force exerted by the car? (2023)

A. 60 N
B. 50 N
C. 70 N
D. 80 N

Solution

Average Force = Work / Distance = 6000 J / 100 m = 60 N

Correct Answer: A — 60 N

Learn More →

Q. If a circuit has a resistance of 5 ohms and a current of 2 amperes, what is the voltage across the circuit?

A. 10 V
B. 5 V
C. 2 V
D. 1 V

Solution

Using Ohm's Law (V = I * R), V = 2 A * 5 Ω = 10 V.

Correct Answer: A — 10 V

Learn More →

Q. If a concave lens has a power of -5 D, what is its focal length? (2021)

A. -20 cm
B. -25 cm
C. -15 cm
D. -10 cm

Solution

Power P = 1/f, thus f = 1/P = 1/(-5) = -0.2 m = -20 cm.

Correct Answer: B — -25 cm

Learn More →

Q. If a cyclist travels at a speed of 15 km/h for 1 hour and then at 20 km/h for 2 hours, what is the average speed for the entire journey? (2022)

A. 17 km/h
B. 18 km/h
C. 19 km/h
D. 20 km/h

Solution

Total distance = 15 km + 40 km = 55 km; Total time = 1 h + 2 h = 3 h; Average speed = Total distance / Total time = 55 km / 3 h = 18.33 km/h.

Correct Answer: B — 18 km/h

Learn More →

Q. If a force of 10 N is applied to an object and it moves 3 m in the direction of the force, what is the work done? (2021)

A. 30 J
B. 20 J
C. 10 J
D. 15 J

Solution

Work done W = F * d = 10 N * 3 m = 30 J.

Correct Answer: A — 30 J

Learn More →

Q. If a force of 15 N is applied at an angle of 60° to the horizontal and moves an object 4 m, what is the work done? (2021)

A. 30 J
B. 60 J
C. 45 J
D. 20 J

Solution

Work done (W) = F × d × cos(θ) = 15 N × 4 m × cos(60°) = 15 N × 4 m × 0.5 = 30 J.

Correct Answer: C — 45 J

Learn More →

Q. If a force of 50 N is applied to move an object 4 m in the direction of the force, what is the work done?

A. 100 J
B. 200 J
C. 150 J
D. 250 J

Solution

Work done W = F × d = 50 N × 4 m = 200 J.

Correct Answer: B — 200 J

Learn More →

Q. If a machine has an efficiency of 80% and it does 400 J of useful work, how much energy was supplied to the machine? (2023)

A. 500 J
B. 400 J
C. 320 J
D. 600 J

Solution

Efficiency = Useful Work / Total Energy Input. Total Energy Input = Useful Work / Efficiency = 400 J / 0.8 = 500 J.

Correct Answer: A — 500 J

Learn More →

Q. If a sound source moves towards a stationary observer, what happens to the frequency heard by the observer?

A. Increases
B. Decreases
C. Remains the same
D. Becomes zero

Solution

As the sound source approaches, the frequency increases due to the Doppler effect.

Correct Answer: A — Increases

Learn More →

Q. If a sound source moves towards an observer, what effect does it have on the frequency heard by the observer?

A. Decreases
B. Increases
C. Remains the same
D. Becomes zero

Solution

The frequency increases due to the Doppler effect when the source moves towards the observer.

Correct Answer: B — Increases

Learn More →

Q. If a sound source moves towards an observer, what happens to the frequency heard by the observer?

A. Increases
B. Decreases
C. Remains the same
D. Becomes zero

Solution

The frequency increases due to the Doppler effect when the source moves towards the observer.

Correct Answer: A — Increases

Learn More →

Q. If a sound wave travels 1 km in 3 seconds, what is its speed?

A. 300 m/s
B. 1000 m/s
C. 333 m/s
D. 500 m/s

Solution

Speed = Distance/Time = 1000 m / 3 s = 333.33 m/s, approximately 333 m/s.

Correct Answer: A — 300 m/s

Learn More →

Q. If a sound wave travels from air into water, what happens to its speed?

A. Increases
B. Decreases
C. Remains the same
D. Becomes zero

Solution

Sound travels faster in water than in air due to higher density.

Correct Answer: A — Increases

Learn More →

Q. If a vehicle travels 100 km in 2 hours and then 50 km in 1 hour, what is its average speed for the entire trip? (2019)

A. 50 km/h
B. 60 km/h
C. 70 km/h
D. 75 km/h

Solution

Total distance = 100 km + 50 km = 150 km; Total time = 2 h + 1 h = 3 h. Average speed = Total distance / Total time = 150 km / 3 h = 50 km/h.

Correct Answer: C — 70 km/h

Learn More →

Q. If a wire carries a current of 3 A and has a resistance of 2 ohms, what is the power dissipated in the wire?

A. 6 W
B. 9 W
C. 12 W
D. 15 W

Solution

Power is given by P = I^2 * R. Here, P = (3 A)^2 * 2 Ω = 9 * 2 = 18 W.

Correct Answer: C — 12 W

Learn More →

Q. If a wire carries a current of 4 A and has a resistance of 2 ohms, what is the power dissipated in the wire?

A. 8 W
B. 16 W
C. 4 W
D. 2 W

Solution

Power (P) is given by P = I^2 * R. Thus, P = (4 A)^2 * 2 Ω = 16 W.

Correct Answer: B — 16 W

Learn More →

Q. If the boiling point of water is 100°C, what is the corresponding temperature in Kelvin? (2021)

A. 273 K
B. 373 K
C. 400 K
D. 450 K

Solution

Temperature in Kelvin (K) = °C + 273 = 100 + 273 = 373 K.

Correct Answer: B — 373 K

Learn More →

Q. If the focal length of a convex lens is 25 cm, what is the power of the lens? (2023)

A. +2 D
B. +4 D
C. +5 D
D. +10 D

Solution

Power P = 1/f (in meters). Thus, P = 1/0.25 = +4 D.

Correct Answer: C — +5 D

Learn More →

Q. If the frequency of an AC circuit is doubled, what happens to the inductive reactance?

A. It doubles
B. It halves
C. It remains the same
D. It quadruples

Solution

Inductive reactance (X_L) is given by X_L = 2πfL. If the frequency (f) is doubled, the inductive reactance also doubles.

Correct Answer: A — It doubles

Learn More →

Q. If the frequency of an AC signal is doubled, what happens to its period?

A. It doubles
B. It halves
C. It remains the same
D. It quadruples

Solution

The period T is the reciprocal of frequency f (T = 1/f). If frequency is doubled, the period halves.

Correct Answer: B — It halves

Learn More →

Q. If the mass of an object is 2 kg, what is its energy equivalent according to Einstein's equation E=mc^2? (2022)

A. 1.8 x 10^16 J
B. 1.8 x 10^14 J
C. 1.8 x 10^12 J
D. 1.8 x 10^10 J

Solution

E = mc^2 = 2 kg * (3 x 10^8 m/s)^2 = 1.8 x 10^16 J.

Correct Answer: A — 1.8 x 10^16 J

Learn More →

Q. If the resistance of a conductor is doubled, what happens to the current if the voltage remains constant? (2020)

A. Doubles
B. Halves
C. Remains the same
D. Increases four times

Solution

According to Ohm's Law, if the resistance is doubled while the voltage remains constant, the current will be halved.

Correct Answer: B — Halves

Learn More →

Q. If the resistance of a wire is 10 ohms and the voltage across it is 20 volts, what is the current flowing through the wire?

A. 2 A
B. 5 A
C. 10 A
D. 20 A

Solution

Using Ohm's Law (I = V/R), I = 20 V / 10 Ω = 2 A.

Correct Answer: A — 2 A

Learn More →

Q. If the resistance of a wire is doubled, what happens to the current if the voltage remains constant? (2021)

A. Doubles
B. Halves
C. Remains the same
D. Increases

Solution

According to Ohm's Law (I = V/R), if the resistance (R) is doubled while the voltage (V) remains constant, the current (I) will be halved.

Correct Answer: B — Halves

Learn More →

Q. If the speed of sound in air is 340 m/s, how long does it take for sound to travel 1 km?

A. 2.94 s
B. 3.5 s
C. 4.5 s
D. 5.5 s

Solution

Time = distance/speed = 1000 m / 340 m/s ≈ 2.94 s.

Correct Answer: A — 2.94 s

Learn More →

Q. If the velocity of an object doubles, what happens to its kinetic energy?

A. It remains the same
B. It doubles
C. It quadruples
D. It halves

Solution

Kinetic energy (KE) is given by KE = 1/2 mv². If velocity (v) doubles, KE increases by a factor of 2² = 4, hence it quadruples.

Correct Answer: C — It quadruples

Learn More →

Q. If the voltage across a resistor is doubled, what happens to the power consumed by the resistor? (2020)

A. It halves
B. It doubles
C. It quadruples
D. It remains the same

Solution

Power (P) is given by P = V^2 / R. If V is doubled, P becomes (2V)^2 / R = 4V^2 / R, which is quadrupled.

Correct Answer: C — It quadruples

Learn More →

Q. If the wavelength of a light wave is doubled, what happens to its frequency? (2020)

A. Doubles
B. Halves
C. Remains the same
D. Quadruples

Solution

Frequency (f) is inversely proportional to wavelength (λ). If λ is doubled, f is halved.

Correct Answer: B — Halves

Learn More →

Showing 121 to 150 of 232 (8 Pages)

Physics

On a scale of 0–10, how likely are you to recommend The Soulshift Academy?