Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

3,756.

An object 4 cm high is placed 15 cm from a concave mirror of focal length 5 cm. The size of the image is?

A.

2 cm

B.

3 cm

C.

4 cm

D.

5 cm

Correct answer is A

(1)/v + (1)/u = (1)/f
(1)/v + (1)/15 = (1)/5
(1)/v = (1)/5 - (1)/15 = (3 - 1)/15 = (2)/15
∴ v = (15)/2 = 7.5 cm
magnification = (v)/u = (image size)/object size
(7.5)/15 = (X)/4
∴ image size. X = (7.5 x 4)/15 = 2 cm

3,757.

In comparing the camera and the human eye, the film of the camera function as the?

A.

retina

B.

iris

C.

cornea

D.

pupil

Correct answer is A

The retina is light sensitive layer living the inner wall of the eye where image is formed. in the camera, image is formed on a light sensitive film.

3,758.

During a thunderstorm, the sound is heard over a long time. this phenomenon is referred to as?

A.

diffraction of sound

B.

refraction of sound

C.

superposition

D.

reveraberation

Correct answer is D

The lengthening effect of sound is known as reverberation.

3,759.

The sound of an electricity bell dies down slowly when air is slowly pumped out from a bottle because

A.

the wavelength of sound becomes greater in the bottle

B.

sound cannot pass through the bottle

C.

sound needs a material medium

D.

sound can pass through a vacuum

Correct answer is C

Sound wave requires a material medium for its propagation. so when air is being pumped out the density of the medium is being reduced and the sound dies down. when all the air has been pumped out of the glass, no sound will be heard, as sound sound cannot travel through vacuum

3,760.

The wavelength of a wave traveling with a velocity of 420 ms-1 is 42 m. what is its period?

A.

1.2 s

B.

1.0 s

C.

0.5 s

D.

0.1 s

Correct answer is D

V = fλ
f = (v)/λ = (420)/42 = 10 HZ
Period, T = (1)/F = (1)/10 = 0.1 secs