JAMB Physics Past Questions & Answers - Page 243

1,211.

A man clapping his hands at regular intervals observes that the echo of a clap coincides with the next clap. If the reflecting cliff is 160m away and the speed of sound is 320ms-1, what is the frequency of the clapping?

A.

1 Hz

B.

2 Hz

C.

4 Hz

D.

8 Hz

Correct answer is A

Total distance = 2 x 160 = 320cm

Total time = \(\frac{320}{320}\) = 1s

F = \(\frac{1}{1}\) = \(\frac{1}{1}\)

= 1Hz

1,212.

Which of the following is true of the loudness of sound? It

A.

depends on the square of the amplitude of the vibrating body

B.

is proportional to the distance of the observer from the source of the sound

C.

is greatest in vacuum

D.

is dependent in vacuum

Correct answer is A

No explanation has been provided for this answer.

1,213.

A wave of frequency 10Hz forms a stationary wave pattern in a medium where the velocity is 20cms-1. The distance between adjacent nodes is

A.

1.0cm

B.

1.5cm

C.

2.0cm

D.

5.0cm

Correct answer is A

\(\lambda\) = \(\frac{v}{f}\)

= \(\frac{20}{10}\)

= 2cm ; distance between adjacent nodes 

= 2cm \ 2 

= 1cm

1,214.

A pencil is placed vertically between a concave mirror and its focal point. The image of the pencil in the mirror will be

A.

real, inverted and diminished

B.

virtual, inverted and enlarged

C.

real, erect and enlarged

D.

virtual, erect and enlarged

Correct answer is D

No explanation has been provided for this answer.

1,215.

What is the effect of the increase in the size of the hole of a pin-hole camera on the image? it

A.

gives a blurred image

B.

corrects for chromatic aberration

C.

magnifies the image

D.

brings the image into a sharper focus

Correct answer is A

No explanation has been provided for this answer.