WAEC Physics Past Questions & Answers - Page 186

926.

Which of the following actions will not cause an increase in the frequency of a vibrating string?

A.

increasing the tension of the string

B.

decrease the mass per unit length of the string

C.

decrease the length of the string

D.

increasing the cross sectional area of the string

Correct answer is D

No explanation has been provided for this answer.

927.

Which of the following instruments is not a wind instrument?

A.

clarinet

B.

saxophone

C.

trumpet

D.

xylophone

Correct answer is D

No explanation has been provided for this answer.

928.

When two notes of nearly equal frequencies are sounded together, a periodic rise and fall in sound intensity can be heard. This phenomenon can be called

A.

beats

B.

diffraction

C.

overtones

D.

resonance

Correct answer is A

No explanation has been provided for this answer.

930.

In a compound microscope, the image formed by the objective lens is at a distance of 3.0cm from the eye lens. Calculate the focal length of the eye lens

A.

0.3cm

B.

2.7cm

C.

3.4cm

D.

8.3cm

Correct answer is C

\(\frac{1}{f} = \frac{1}{u} + \frac{1}{v} = \frac{1}{3} - \frac{1}{25} = \frac{22}{75}\)

f = 3.4cm