JAMB Physics Past Questions & Answers - Page 308

1,536.

If a solid X floats in liquids P of relative density 2.0 and in liquid Q of relative density 1.5, it can be inferred that the

A.

weight of P displaced is greater than that of Q

B.

weight of P displaced is less than that of Q

C.

volume of P displaced is greater than that of Q

D.

volume of P displaced is less than that of Q

Correct answer is A

R.d \(\alpha\) weight of liquid displaced

\(\frac{\text {R.d of P}}{\text {R.d of Q}}\) = \(\frac{\text{weight of p displaced}}{\text{weight of Q displaced}}\)

\(\frac{2}{1.5}\) = \(\frac{\text {weight of p displaced}}{\text {weight of Q displaced}}\)

1,537.

The mass of a specific gravity bottle is 15.2g when it is empty. it is 24.8g when filled with kerosene and 27.2g when filled with distilled water. Calculate the relative density of kerosene

A.

1.25

B.

1.10

C.

0.90

D.

0.80

Correct answer is D

Masses of kerosene = 24.8 - 15.2

= 9.6

mass of H2O = 27.2 - 15.2

= 12

R.d = \(\frac{9.6}{12}\) = 0.8

1,540.

Calculate the velocity ratio of a screw jack of pitch 0.3cm if the length of the tommy bar is 21cm

A.

\(\frac{1}{140}\)\(\pi\)

B.

14\(\pi\)

C.

70\(\pi\)

D.

140\(\pi\)

Correct answer is D

V.R = \(\frac{2\pi L}{p}\)

= \(\frac{2 \times \pi \times 2}{0.3}\)

V.R = 140\(\pi\)