JAMB Physics Past Questions & Answers - Page 261

1,301.
1,302.

A tap supplies water at 25oC while another supplies water at 75oC. If a man wishes to bathe with water at 40oC, the ratio of the mass of cold water to the mass of hot water required is

A.

1 : 3

B.

15 : 8

C.

7 : 3

D.

3 : 1

Correct answer is C

Heat lost = heat gained

mh x c x (75 - 40) = mc x c x (40 - 25)

\(\frac{m_h}{m_c}\) = \(\frac{35}{15}\)

= \(\frac{7}{3}\)

1,303.

The amount of heat needed to raise the temperature of 10kg of copper by 1k is its

A.

specific heat capacity

B.

heat capacity

C.

latent heat

D.

internal energy

Correct answer is B

No explanation has been provided for this answer.

1,304.

The product PV where P is pressure and V is volume has the same unit as

A.

force

B.

power

C.

energy

D.

accelaration

Correct answer is C

PV = \(\frac{N}{m^2}\) x \(\frac{m^3}{1}\)

= Nm

= Force x distance = work done = energy

1,305.

A body whose mass is 2kg and has a volume of 500cm3 just floats when completely immersed in a liquid. Calculate the density of the liquid

A.

4.0 x 102kgm-3

B.

4.0 x 103kgm-3

C.

1.0 x 103kgm-3

D.

1.0 x 106kgm-3

Correct answer is B

since the object floats, density of liquid = density of object

converting 500cm3 to m3,

\(\frac{500}{10^{6}} = 5 \times 10^{-4}m^{3}\)

D = \(\frac{m}{v}\)

= \(\frac{2}{5 \times 10^{-4}}\)

=\(4.0 \times 10^{3}kgm^{-3}\)