Q. The critical angle of light going from medium A into medium B is θ. The speed of light in medium A is v. The speed of light in medium B is

(a) v/sinθ

(b) v sinθ

(c) v/tanθ

(d) v tanθ

Ans: (a)

Sol: μ_{A}sinθ = μ_{B}sin90

sinθ = μ_{B}/μ_{A } …..(i)

v_{A}/v_{B} = (c/μ_{B})/(c/μ_{A}) = μ_{B}/μ_{A} = sinθ from(i)

v_{B} = v_{A}/sinθ = v/sinθ