JAMB Physics Past Questions & Answers - Page 383

1,911.

An object is placed 5 cm from the pole of a concave mirror. if the focal length of the mirror is 10 cm. what is the image distance?

A.

10 cm in front of the mirror

B.

5 cm in front of the mirror

C.

10 cm behind the mirror

D.

5 cm behind the mirror

Correct answer is C

u = 5 cm , f = 10 cm, v = ?
(1)/v + (1)/u = (1)/f
(1)/v + (1)/5 = (1)/10
= (1)/v = (1)/10 - (1)/5

= (1 - 2)/10 = (1)/10
∴ v = - 10 cm
∴ The image is 10 cm behind the mirror

1,912.

I. Moon.
II. Sun.
III.street light.
IV. stars.
Which of these are natural sources of light?

A.

II, III, and IV only

B.

I, II and III only

C.

III and IV only

D.

II and IV only

Correct answer is D

The sun and stars are self luminous object.

1,913.

Musical instruments playing the same note can be distinguished from one another owing to the differences in their?

A.

quality

B.

pitch

C.

intensity

D.

loudness

Correct answer is A

The quality of a note is a characteristic that distinguishes it from note of the same frequency played by another musical instrument.

1,914.

A man standing 2 m from a charcoal fire is warmed mainly by?

A.

convection

B.

radiation

C.

refraction

D.

conduction

Correct answer is B

Radiation is the method of heat transfer with or without a material medium. It can be through space or through a material medium.

1,915.

It is observed that water will wet a clean glass because the?

A.

cohesion of water to glass is stronger than the cohesion of water molecules

B.

adhesion of water molecules is weaker than the cohesion of water to glass

C.

cohesion of water to glass is weaker than the cohesion of water molecules

D.

adhesion of water molecules is stronger than the cohesion of water molecules

Correct answer is D

When the adhesion of liquid molecules to the glass is more than the cohesion of the liquid, the liquid will wet glass.