4) a) Velocity of light in air / vacuum is 'C' and that in a given medium B is 'v'. Give the expression for the refractive index of medium B with respect to air / vacuum. b) The absolute refractive index of glass is 1.5. Find the speed of light in glass. C = 3 x 108 ms.
Answers
Answer:
Given : n
water
=
3
4
n
glass
=
2
3
v
glass
=2×10
8
m/s n
air
=1
Speed of light in a medium v
medium
=
n
c
where c and n are the speed of light in vacuum and refractive index of medium respectively.
(a) : v
glass
=
n
glass
c
∴ 2×10
8
=
(3/2)
c
⟹c=3×10
8
m/s
(b) : v
water
=
n
water
c
∴ v
water
=
(4/3)
3×10
8
=2.26×10
8
m/s
Answer
b)2 * 10 ^ 8 ms-^1
Explanation:
b)It is there in the examples of NCERT not directly but in a round about way you can check.
Well , my explanation
speed of light in vacuum/ speed of light in glass is equal to 1.5
3* 10^8 m/s /1.5 = speed of light in glass
=2* 10^ 8 m/s
If you have trouble memorising the formula of refractive index just remember this- refractive index with respect to / refractive index of.
for part (a) your question seems a bit wrong.