© examsnet.com
Question : 6
Total: 12
What happens to a beam of white light when it gets refracted through glass prism ? Which colour deviates the most and the least after refraction through a prism ? What is likely to happen if a second identical prism is placed in an inverted position with respect to the first prism. Justify your answer.
OR
A student needs spectacles of power− 0.5 D
(i) Name the defect in vision the student is suffering from.
(ii) Find the nature and focal length of the corrective lens.
(iii) List two causes of this defect.
OR
A student needs spectacles of power
(i) Name the defect in vision the student is suffering from.
(ii) Find the nature and focal length of the corrective lens.
(iii) List two causes of this defect.
Solution:
When white light is refracted through a glass prism, it gets split into its constituting colours at different angles. This phenomenon is called Dispersion of Light. Example-Formation of a rainbow,
When second identical prism is placed in an inverted position with respect to first prism, recombination of the spectrum will take place and white light will be obtained.
OR
(i) Myopia.
(ii) Concave lens with the focal length of200 cm
Given,P = − 0.5 D
We have,
P =
m
f =
=
f = − 2 m
f = − 200 cm
(iii) Two causes of Myopia are :
(a) Elongation of eye ball.
(b) High converging power of eye lens.
Least deviated colour is red whereas most deviated colour is violet.
When second identical prism is placed in an inverted position with respect to first prism, recombination of the spectrum will take place and white light will be obtained.
OR
(i) Myopia.
(ii) Concave lens with the focal length of
Given,
We have,
(iii) Two causes of Myopia are :
(a) Elongation of eye ball.
(b) High converging power of eye lens.
© examsnet.com
Go to Question: