JAMB Physics Past Questions & Answers - Page 219

1,091.

The specific latent heat of vaporization of a substance is always?

A.

less than its specific latent heat of fusion

B.

greater than its specific heat of fusion

C.

equal to its specific latent heat of fusion

D.

all of the above depending on the nature of the substance

E.

none of the above

Correct answer is B

No explanation has been provided for this answer.

1,092.

If the force of a charge of 0.2 coulomb in an electric field is 4N, then the electric field intensity of the field is

A.

0.8

B.

0.8N/C

C.

20.0N/C

D.

4.2N/C

Correct answer is C

Field intensity = \(\frac{force}{charge}\)

\(\frac{4}{0.2}\) = 20N/C

1,093.

The speed of light in vacuum is 3.0 x 108ms-1. If the refractive index of a transparent liquid is \(\frac{4}{3}\), then the speed of light in the liquid is

A.

0.44 x 10 8ms-1

B.

2.25 x 10 8ms-1

C.

3.0 x 10 8ms-1

D.

4.0 x 10 8ms-1

E.

4.33 x 10 8ms-1

Correct answer is B

n = \(\frac{\text{speed in air }}{\text{speed in water }}\)

\(\frac{4}{3}\) = \(\frac{3 \times 10^8}{v}\)

v = 2.25 x 108ms-1

1,094.

Which of the following best describes the energy changes which take place when a steam engine drives a generator which lights a lamp?

A.

heat \( \to \) light \( \to \) sound \( \to \) kinetic

B.

kinetic \( \to \) light \( \to \) heat \( \to \) electricity

C.

heat \( \to \) kinetic\( \to \) electricity \( \to \) heat \( \to \) light

D.

electricity \( \to \) kinetic \( \to \) heat \( \to \) light

E.

heat \( \to \) sound \( \to \) kninetic \( \to \) electricity

Correct answer is C

No explanation has been provided for this answer.

1,095.

The difference of potential between the terminals of cells is 2.2 volts. When a 4ohm resistor is connected across the terminals of this cells, the potential difference is 2 volts. What is the internal resistance of the cell?

A.

0.10 ohms

B.

0.25 ohms

C.

0.40 ohms

D.

2.50 ohms

E.

4.00 ohms

Correct answer is C

IR = 2 and Ir = 0.2

I = \(\frac{2}{R}\) ; I = \(\frac{0.2}{r}\)

\(\frac{2}{4}\) = \(\frac{0.2}{r}\)

r = 0.4\(\Omega\)