JAMB Physics Past Questions & Answers - Page 251

1,251.

A pool of water appears to be 1.0m deep when viewed vertically from above. If the refractive index of water is 1.33, what is the actual depth of the pool?

A.

0.750m

B.

1.013m

C.

1.330m

D.

13.3000m

Correct answer is C

n = \(\frac{\text {real depth}}{\text{apparent depth}}\)

1.33 = \(\frac{\text {real depth}}{1}\)

real depth = 1.33cm

1,252.

An object 3.0cm high is placed 60.0cm from a converging lens whose focal length is 20.0cm. Calculate the size of the image formed

A.

0.5cm

B.

1.5cm

C.

2.0cm

D.

6.0cm

Correct answer is B

F = \(\frac{UV}{U + V}\)

20 = \(\frac{60 \times V}{60 + V}\)

V = 30cm

similarly, \(\frac{U}{V}\) = \(\frac{\text{height of object}}{\text{height of image}}\)

\(\frac{60}{30}\) = \(\frac{3}{h}\)

h = 1.5cm

1,253.

If an object is placed in front of two mirrors inclined at 90o, how many images will be formed?

A.

five

B.

four

C.

three

D.

two

Correct answer is C

n = \(\frac{360}{\theta}\) - 1

= 360 - 1

= 3 images

1,254.

When the length I of a piece of wire under constant tension is varied, the relationship of the frequency of the vibration f\(\alpha\)/ is

A.

f\(\alpha\)/

B.

f\(\alpha \frac{1}{I^2}\)

C.

f \(\alpha\sqrt I\)

D.

f\(\alpha \frac{1}{1}\)

Correct answer is D

F = \(\frac{1}{2L}\sqrt\frac{T}{m}\)

1,255.

Which of the following statements supports the assumption that light travels in straight lines?

A.

light can be diffracted

B.

a source of light produces distinct shadows of opaque objects

C.

a source of light produces interference patterns on a suitably placed screen

D.

light can be reflected

Correct answer is B

No explanation has been provided for this answer.