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Question: The angle of minimum deviation from prism of angle \(3 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }\)th...

The angle of minimum deviation from prism of angle 3×108 ms13 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }then the velocity of light in material of the prism is :

A

2.12×108 ms12.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

B

1.12×108 ms11.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

C

4.12×108 ms14.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

D

5.12×108 ms15.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

Answer

2.12×108 ms12.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

Explanation

Solution

: Using,

Here, A=π3=60,δm=π6=30,c=3×108 ms1\mathrm { A } = \frac { \pi } { 3 } = 60 ^ { \circ } , \delta _ { \mathrm { m } } = \frac { \pi } { 6 } = 30 ^ { \circ } , \mathrm { c } = 3 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }

μ=sin(60+30)/2sin60/2=070710.50=1.414\therefore \mu = \frac { \sin \left( 60 ^ { \circ } + 30 ^ { \circ } \right) / 2 } { \sin 60 ^ { \circ } / 2 } = \frac { 07071 } { 0.50 } = 1.414

Therefore,

v=2.12×108 ms1\mathrm { v } = 2.12 \times 10 ^ { 8 } \mathrm {~ms} ^ { - 1 }