Physics MCQs

Question #901

Share Report

The half-life of a radioactive element is 5 days. After 20 days, the fraction undecayed is

A. 1/16

B. 1/8

C. 1/2

D. 1/4

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
4 half-lives => (1/2)^4 = 1/16.

This question belongs to: Science Physics

Question #902

Share Report

The frequency of a pendulum is 0.5 Hz. Its time period is

A. 0.5 s

B. 5 s

C. 1 s

D. 2 s

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
T = 1/f = 1/0.5 = 2 s.

This question belongs to: Science Physics

Question #903

Share Report

A wave has speed 300 m/s and frequency 150 Hz. Wavelength is

A. 45000 m

B. 0.5 m

C. 300 m

D. 2 m

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
λ = v/f = 300/150 = 2 m.

This question belongs to: Science Physics

Question #904

Share Report

The least count of a standard vernier calliper is generally

A. 0.001 cm

B. 1 cm

C. 0.1 cm

D. 0.01 cm

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Least count = 1 MSD - 1 VSD = 0.1 - 0.09 = 0.01 cm (common).

This question belongs to: Science Physics

Question #905

Share Report

The unit of power is watt. It is equal to

A. N/s

B. J/s

C. N m

D. J s

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Watt = joule / second.

This question belongs to: Science Physics

Question #906

Share Report

When a body falls freely under gravity, its

A. Mass increases

B. P.E. increases

C. K.E. decreases

D. Mechanical energy remains constant

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Neglecting air resistance, total mechanical energy conserved.

This question belongs to: Science Physics

Question #907

Share Report

The centre of gravity of a uniform sphere is at

A. Midpoint of radius

B. Geometric centre

C. Surface

D. Outside sphere

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
For uniform sphere, centre of gravity is at centre.

This question belongs to: Science Physics

Question #908

Share Report

A man pushes a wall but fails to move it. Work done is

A. Negative

B. Maximum

C. Positive

D. Zero

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Displacement zero, so work zero.

This question belongs to: Science Physics

Question #909

Share Report

A pump lifts 100 kg of water through 5 m in 2 s. Power (g=10) is

A. 2500 W

B. 500 W

C. 1000 W

D. 250 W

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Work = 100×10×5=5000 J. Power = 5000/2 = 2500 W.

This question belongs to: Science Physics

Question #910

Share Report

The dimensional formula for torque is same as

A. Work

B. Impulse

C. Force

D. Power

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Torque = force × distance = [ML²T⁻²], same as work and energy.

This question belongs to: Science Physics

Question #911

Share Report

A body is thrown vertically upwards with kinetic energy 100 J. At highest point, kinetic energy is

A. 50 J

B. 100 J

C. 0 J

D. 200 J

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
At highest point velocity zero, so K.E. = 0. All converted to P.E.

This question belongs to: Science Physics

Question #912

Share Report

A 5 Ω resistor dissipates 20 W power. Current through it is

A. 0.5 A

B. 2 A

C. 100 A

D. 4 A

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
P = I² R => I = √(P/R) = √(20/5) = √4 = 2 A.

This question belongs to: Science Physics

Question #913

Share Report

The colour with maximum wavelength in visible spectrum is

A. Blue

B. Green

C. Violet

D. Red

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option D

Explanation:
Red ~700 nm.

This question belongs to: Science Physics

Question #914

Share Report

Which of the following is a good conductor of heat?

A. Wood

B. Silver

C. Plastic

D. Air

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Silver excellent conductor. Air is insulator.

This question belongs to: Science Physics

Question #915

Share Report

The temperature of a body is 122°F. In Celsius it is

A. 122°C

B. 50°C

C. 90°C

D. 30°C

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
C = (122-32)×5/9 = 90×5/9 = 50°C.

This question belongs to: Science Physics

Question #916

Share Report

The image formed on retina is

A. Virtual and inverted

B. Virtual and erect

C. Real and inverted

D. Real and erect

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Real inverted image, brain interprets as erect.

This question belongs to: Science Physics

Question #917

Share Report

The device used to hear heartbeats is

A. Microscope

B. Telescope

C. Stethoscope

D. Endoscope

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Stethoscope amplifies sound.

This question belongs to: Science Physics

Question #918

Share Report

The speed of light in vacuum is approximately

A. 3 × 10⁴ m/s

B. 3 × 10⁶ km/s

C. 3 × 10⁸ m/s

D. 3 × 10⁵ m/s

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
3×10⁸ m/s = 3×10⁵ km/s.

This question belongs to: Science Physics

Question #919

Share Report

The mass of a proton is about _____ times the mass of an electron.

A. 1836

B. 2000

C. 100

D. 1000

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Proton mass 1.67×10⁻²⁷, electron 9.11×10⁻³¹, ratio ~1836.

This question belongs to: Science Physics

Question #920

Share Report

An element X has atomic number 17 and mass number 35. Number of neutrons is

A. 52

B. 35

C. 18

D. 17

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option C

Explanation:
Neutrons = 35 - 17 = 18 (Chlorine).

This question belongs to: Science Physics

Practice Questions

More Science Topics