JAMB Physics Past Questions & Answers - Page 292

1,456.

Which of the following characteristics of a wave is used in the measurement of the depth of the sea?

A.

diffraction

B.

interference

C.

refraction

D.

reflection

Correct answer is D

No explanation has been provided for this answer.

1,457.

The equation of a wave is y = 0.005 sin[x(0.5X - 200t)] where x and y are in meters and t is in seconds. What is the velocity of the wave?

A.

4000ms-1

B.

400ms-1

C.

250ms-1

D.

40ms-1

Correct answer is B

y = 0.005 sin[x(0.5X - 200t)]

compare to Y = A sin(kx - wt)

\(\lambda\) = \(\frac{2\pi}{k}\) and F = \(\frac{w}{2\pi}\)

V= \(\lambda\)F

= \(\frac{2\pi}{0.5}\) x \(\frac{200}{2\pi}\)

= 400ms-1

1,458.

The space between the double glass walls of a thermos flask is evacuated space are silvered. The residual source of heat loss takes place by

A.

convection

B.

radiation from the surface

C.

conduction through the stopper and the glass

D.

conduction across the walls

Correct answer is C

No explanation has been provided for this answer.

1,459.

A block of ice floats on water inside a container. If the block of ice gets completely melted, the level of water in the container will

A.

increase

B.

remain the same

C.

decrease

D.

first decrease and then increase

Correct answer is B

No explanation has been provided for this answer.

1,460.

How much heat is absorbed when a block of copper of mass 0.05kg and specific heat capacity 390Jkg-1K-1 is heated from 20oC to 70oC?

A.

39 . 98 x 10-1J

B.

9.75 x 102J

C.

3.98 x 103J

D.

9.75 x 103J

Correct answer is B

Q = mc\(\theta\)

= 0.05 x 390 x (70 - 20)

= 975J