A thin prism of refracting angle 10 produces a deviation of 5 in a ray of light passing through it. Find the refractive index of the prism material and the velocity of light in it.
Answers
Explanation:
A thin prism having refracting angle 10
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is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be :
Given:
A thin prism of refracting angle 10 produces a deviation of 5 in a ray of light passing through it.
To find:
Find the refractive index of the prism material and the velocity of light in it.
Solution:
From given, we have,
A thin prism of refracting angle 10 produces a deviation of 5 in a ray of light passing through it.
The refractive index of the prism material
d = (μ - 1) A
5 = (μ - 1) 10°
5/10 = μ - 1
0.5 + 1 = μ
∴ μ = 1.5
The velocity of light in prism.
μ = c/v
v = c/ μ
v = 3 × 10⁸ / 1.5
∴ v = 2 × 10⁸ m/s
Therefore, the refractive index of the prism material and the velocity of light in it are 1.5 and 2 × 10⁸ m/s respectively.