Question

a Ray of light starts to travel from median1 to medium 2 if angle in medium 1 and 2 are 45 degree and 30 degree the speed of light in medium 1 is 2.5 multiply 10 to the power 8 m/S find the speed of the light in medium 2​

Answer 1

ANSWER

we know that refractive index n=speedoflightinmediumspeedoflightinvacuum​

where c=3×108m/s

1.5=vc​

v=1.53×108​

v=2×108m/s

For critical angle we will use snell's law

C is critical angle

nglass​sinC=nair​sin90     nair​=1

sinC=nglass​1​=1.51​

C=41.8o

Answer 2

Answer:

Explanation:

Velocity in (denser) medium M1​        v1​=1.5×108 m/s

Velocity in (rarer) medium M2​        v2​=2×108 m/s

For total internal reflection to occur, the angle of incidence (θ) must be greater than critical angle θc​.

∴     θ>sin−1(nd​nr​​)

Using   nd​nr​​=v2​v1​​ we get    θ>sin−1(v2​v1​​)

∴  θ>sin−1(2×1081.5×108​)               ⟹   θ>sin−1(43​)