JAMB Physics Past Questions & Answers - Page 390

1,946.

I. Total internal reflection of light.
II. Conservation of light energy.
III. Relative motion of the earth, sun and moon.
IV. Rectilinear propagation of light.
which of the above is a phenomenon of total solar eclipse?

A.

I and IV only

B.

II and IV only

C.

I and III only

D.

III and IV only

Correct answer is D

Due to rectilinear propagation of light we have ecslipse which occur as a result relative motion of the earth, sun and moon

1,947.

The fundamental property of a propagating wave which depends only on the source and not the medium of propagation is the?

A.

wavelength

B.

harmonics

C.

frequency

D.

velocity

Correct answer is C

Timber/ quality depends on the overtones or harmonics, and timber is a characteristic property of source of sound,

A harmonic is a wave with a frequency that is a positive integer multiple of the fundamental frequency,

These rest on the fundamental property of FREQUENCY.

1,948.

Given the progressive wave equation y = 5 sin (2000 πt - 0.4x), calculate wave length

A.

12.4 m

B.

15.7 m

C.

17.5 m

D.

18.6 m

Correct answer is B

Comparing y = 5sin (200 πt - 0.4X) with the wave equation y = A sin (wt -KX) K = (2π)/λ = 0.4
∴ λ = (2π)/0.4 = 15.7M

1,949.

In a good thermos flask, heat loss is reduced through the following features EXCEPT?

A.

the lens surface

B.

the insulating cork

C.

silvered walls

D.

the cork lid

Correct answer is A

The silver coating on the inner bottle of a thermos flask is used to prevent heat transfer by radiation

1,950.

If the partial pressure of water vapour at 27°C is 18 mm Hg and the saturated vapour pressure of the atmosphere at the same temperature is 24 mm Hg, the relative humidity at this temperature is?

A.

25%

B.

33%

C.

75%

D.

82%

Correct answer is C

Relative
Humidity = (S.V.P. of water at dew point)/S.V.P of water at air temperature =(18)/24 x 100% = 75%