WAEC Physics Past Questions & Answers - Page 173

861.

The bar magnet illustrated in the diagram above picks up an unmagnetised steel nail X. In turn, X picks up a similar nail Y and so on. The nail are said to be magnetised by

A.

conduction

B.

single touch

C.

induction

D.

divided touch

Correct answer is C

No explanation has been provided for this answer.

862.

The diagram above represent displacement D, versus time, t graph of a progressive wave. Deduce the frequency of the wave

A.

20 Hz

B.

10 Hz

C.

5 Hz

D.

4 Hz

Correct answer is B

No explanation has been provided for this answer.

863.

Calculate the change in volume when 90g of ice is completely melted. [density of water = 1g cm-3, density of ice = 0.9cm-3]

A.

0.00cm3

B.

9.00cm3

C.

10.00cm3

D.

90.00cm3

Correct answer is C

\(\Delta\)y = Vice - Vwater

= \(\frac{90}{0.9} - \frac{90}{1} = 10cm^3\)

864.

An object weighs 60.0N in air, 48.2N in a certain liquid X, and 44.9N in water, Calculate the relative density of X

A.

3.300

B.

1.279

C.

0.932

D.

0.782

Correct answer is D

R.d = Wt in Air-Wt in Air-Wt in water

= \(\frac{60.0 - 48.2}{60.0 - 44.9}\)

= 0.782

865.

Which of the following statements about the mass and the weight of a body is not correct? its

A.

mass is a scalar quantity

B.

weight is a function of the gravitational pull on it

C.

mass on earth and on the moon is the same

D.

weigh at the equatior and at the poles is the same

Correct answer is D

No explanation has been provided for this answer.