1.A monochromatic ray of light after passing through the prism produces
a) seven colours only b) five colours only
c) two colours only
d) one colour only
2.For a ray of light incident on a prism of angle A, the wrong statement is
a) The angle of deviation will increase as A is increased.
b) The angle of deviation will increase as the refractive index of the prism is increased.
c) The angle of deviation for violet colour is more than the angle of deviation for red colour
d) All colours into which the ray is dispersed emerges as a parallel beam.
3.In the study of the spectrum, the prism is placed in minimum deviation position to make the spectrum
b) magnified
c) line spectrum
d) well defined i
a) visible
Answers
Answer:
1.(a)seven colours only
2.(a) The angle of deviation will increase as A is increased.
3.b) magnified
1. A monochromatic ray after passing through prism produces seven colors only (Option a)
When monochromatic light is incident on a prism, it splits into its seven constituent colors (VIBGYOR) by the process of dispersion. This band of seven colors is known as spectrum.
2. For a ray of light incident on a prism of angle A, the wrong statement is the angle of deviation will increase as A is increased (Option a)
For the angle of minimum deviation, δ = 2i - A. Therefore, the angle of deviation will decrease if A is increased.
3. In the study of spectrum, the prism is placed at minimum deviation to make the spectrum well defined (Option d).
At the angle of minimum deviation, the spectrum becomes distinct.