WAEC Physics Past Questions & Answers - Page 216

1,076.

The shortest length of the air column in a resonance tube at resonance is 0.12m and the next resonance length is 0.37m. Calculate the frequency of vibration given that the speed of sound in air is 340m^-1

1360Hz

694Hz

680Hz

34Hz

340Hz

View answer & explanation

Correct answer is C

f = \(\frac{v}{2(l_2 - l_1)} = \frac{340}{2(0.37 - 0.12)} = \frac{34}{0.5}\) = 680

1,077.

The intensity of light falling on the film in a camera depend on the

i. brightness of the object.
ii. diameter of the aperture stop.
iii. speed of the shutter.

Which of the statements is/are correct?

i, ii and iii

i and ii only

ii and iii only

iii only

View answer & explanation

Correct answer is E

No explanation has been provided for this answer.

1,078.

A lantern gives an image of 3m square of a slide 7.62cm square on a screen. If the screen is 10m from the projection lens of the lantern, calculate the focal length of the lens

40.3cm

26.1cm

24.8cm

0.7cm

0.3cm

View answer & explanation

Correct answer is C

M = \(\frac{V_H}{U_H} = \frac{300}{7.62}\)

= 39.3

U = \(\frac{V}{M} = \frac{1000}{39.3}\) = 25.44

\(\frac{1}{f} = \frac{I}{U} + \frac{I}{V} = \frac{I}{25.44} = \frac{I}{1000} = \frac{1025.44}{25440}\)

f = \(\frac{25440}{1025.44} = 24.8\)

1,079.

An astronomical telescope having an objective of focal length 100cm and an eyepiece of focal length 10cm is used in normal adjustment, calculate the separation of the lenses

0.10m

0.90cm

1.10m

1.80m

2.20m

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

1,080.

A converging lens of focal length 5cm is used as a magnifying glass by a man whose nearpoint is 35cm. Calculate the magnification given by the lens

View answer & explanation

Correct answer is C

\(\frac{1}{f} = \frac{1}{u} + \frac{1}{v}\)

= \(\frac{1}{5} - \frac{1}{35} = \frac{30}{175}\)

U = \(\frac{175}{30}\) = 5.8m

\(\frac{v}{u} = \frac{35}{5.8}\)

= 6