A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc, which should be placed over the source, on the surface of water to cut-off all light coming out of water
a)
Infinite
b)
6 m
c)
4 m
d)
3m
A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc, which should be placed over the source, on the surface of water to cut-off all light coming out of water
a)
Infinite
b)
6 m
c)
4 m
d)
3m
Question ID - 152522 | SaraNextGen Top Answer
A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc, which should be placed over the source, on the surface of water to cut-off all light coming out of water
a)
Infinite
b)
6 m
c)
4 m
d)
3m
|
A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc, which should be placed over the source, on the surface of water to cut-off all light coming out of water |
|||||||
|
a) |
Infinite |
b) |
6 m |
c) |
4 m |
d) |
3m |
1 Answer
127 votes
Answer Key / Explanation : (b) -
|
(b) Let
From
Hence, diameter |
be the light source. If light falls on the surface at critical angle 
it grazes along the surface as shown.
we have
127 votes
Answer Link
127