WAEC Physics Past Questions & Answers - Page 178

886.

A sonometer wire of linear density 0.08kg m-1 subjected to a tension of 800N is plucked. Calculate the speed of a pulse which moves from one end of the wire to the other

A.

179.0ms-1

B.

100.0ms-1

C.

15.8ms-1

D.

8.0ms-1

Correct answer is B

v = \(\sqrt{\frac{T}{m}} = \sqrt{\frac{800}{0.08}} = 100\)m/s

887.

The speed of sound in air is directly proportional to

A.

its temperature on the celsius scale

B.

its temperature in the thermodynamic scale

C.

the cube root of its temperature on its celcius scale

D.

the square roor of its temperature on the absolute scale

Correct answer is D

No explanation has been provided for this answer.

888.

Which of the following statements about the human eye and the camera is correct?

A.

both form virtual image of objects

B.

the image formed by the eye is upright in the retina while that formed by the camera is inverted on the film

C.

the inside of both of them is blackened to absorb unwanted light

D.

the focal length of both eye lens and the camera lens can be varied

Correct answer is C

No explanation has been provided for this answer.

889.

Which of the following pairs of rays shows the widest separation in the spectrum of white light?

A.

green and blue

B.

orange and indigo

C.

blue and violet

D.

red and yellow

Correct answer is B

No explanation has been provided for this answer.

890.

A converging lens has a focal length of 5cm. Determine its power

A.

+20.0

B.

+0.2

C.

-20.00

D.

-0.2

Correct answer is A

p = \(\frac{100}{f} = \frac{100}{+5} = +20\)