WAEC Physics Past Questions & Answers - Page 197

981.

A piece of cloth appears green in sunlight. When held in red light, it will appear

A.

green

B.

blue

C.

red

D.

black

Correct answer is D

No explanation has been provided for this answer.

983.

Convex spherical mirrors are preferred to plane mirrors as driving mirrors because

A.

the image produce is upright and clearly visible

B.

it provides a wider field of view

C.

the image produce is errect and diminished

D.

the image produced is not laterally inverted

Correct answer is B

No explanation has been provided for this answer.

985.

Surface waves travelling in deep water at 15ms-1 are incident at a shallow water boundary. If the angles of incidence and refraction are 45o and 30o respectively. Calculate the speed of the waves in shallow water

A.

8.1ms-1

B.

10.0ms-1

C.

10.6ms-1

D.

22.5ms-1

Correct answer is C

n = \(\frac{\sin 45}{\sin 30} = 1.4142\)

n = \(\frac{15m/s}{x}\)

x = \(\frac{15}{1.4142}\) = 10.6m/s