JAMB Physics Past Questions & Answers - Page 282

1,407.

Which of the following correctly, describes the image of an object, 4cm from a diverging lens of focal length 12cm?

A.

The image is virtual, 3cm in front of the lens

B.

The image is real, 6cm behind the lens

C.

The image is virtual, 6cm in front of the lens

D.

The image is real, 3cm in front the lens

Correct answer is A

F = \(\frac{uv}{u + v}\)

F = -ve

-12 = \(\frac{4 \times v}{4 + v}\)

v = -3cm

1,408.

In a ray diagram for a thin converging lens, a ray that is not parallel to the optic axis but passes through the optic center will

A.

pass through undeviated

B.

pass through the center of curvature after refraction

C.

emerge parallel to the principal axis

D.

pass through the principal focus after refraction

Correct answer is A

No explanation has been provided for this answer.

1,409.

A trough 12.0cm deep is filled with water of refractive index \(\frac{4}{3}\). By how much would a coin at the bottom of the trough appear to be displaced when viewed vertically from above the water surface?

A.

3.0cm

B.

6.0cm

C.

9.0cm

D.

16.0cm

Correct answer is A

\(\frac{4}{3}\) = \(\frac{12}{\text {Apparent depth}}\)

Apparent depth = 9cm

Height by which coin is raised = 12 - 9

= 3cm

1,410.

When a plane mirror at which a ray is incident is rotated through an angle \( \theta \), the reflected ray will be rotated through

A.

\(\frac{1}{2}\)\(\theta\)

B.

\(\theta\)

C.

2\(\theta\)

D.

3\(\theta\)

Correct answer is C

No explanation has been provided for this answer.