Question

If the critical angle for total internal reflection from a medium to vacuum is 30⁰ the velocity of light in the medium is –

• A. 3 × 10⁸ m/s
• B. 1.5 × 10⁸ m/s
• C. 6 × 10⁸ m/s
• D. $\sqrt { 3 }$ × 10⁸ m/s

Answer 1

Answer: (B)

1.5 × 10⁸ m/s

Answer 2

Sin i_c = = $\frac { \mu _ { \mathrm { r } } } { \mu _ { \mathrm { d } } }$ =

sin 30⁰ = Ž v_d = 1.5 × 10⁸ m/s