JAMB Physics Past Questions & Answers - Page 180

896.

Of the following, which is different from the others?

A.

x-rays

B.

gamma-rays

C.

cathode rays

D.

ultra violet rays

E.

infrared rays

Correct answer is C

No explanation has been provided for this answer.

897.

For the correction of myopic defects in the human eye we require

A.

a convex lens

B.

a concave lens

C.

a combination of concave and convex lenses

D.

a prism

E.

a concave mirror

Correct answer is B

No explanation has been provided for this answer.

898.

A string is sustaining a stationary wave when

A.

the frequency of the wave is not proportional to the wavelength of the wave

B.

the amplitude of vibration is always zero

C.

two equal waves are travelling in opposite directions

D.

the waves are longitudinal

E.

the frequency is directly proportional to the length of the string

Correct answer is C

-Standing waves are produced on a string when equal waves travel in opposite directions.

-A stretched string is fixed at both ends, when it is plucked at mid point, two reflected waves of same amplitude and frequency at the ends are travelling in opposite direction and overlap along the length. Then the resultant waves are known as the standing waves (or) stationary waves.

899.

The angular dispersion of a prism depends on

A.

the index of refraction only

B.

the angle of incidence as well as the index of refraction

C.

the angle of incidence only

D.

the thickness of the prism

E.

the prism angle

Correct answer is A

No explanation has been provided for this answer.