Question

A beam of light (c = 3E + 8 m/s) in the air strikes the surface of a rectangular block of transparent plastic (n = 1.49). What is its velocity within the block? Select one: to. 3.00E + 8 m/s b. 1.35E + 8 m/s c. 2.01 E + 8 m/s d. 2.46E + 8 m/s

Answer 1

1.

C = 3× 10 ⁸ m/s

Refractive index of glass n = 1.49

n = C/v

v = speed of light

v = C / n

v = ( 3× 10 ⁸ m/s ) / 1.49

v = 2.01× 10 ⁸ m/s

2.

Ans : 0.5

When an unpolarized light is passed through a polarizer , the intensity is reduced by a factor of 1/2 .

By Mallus law

I _transmitted = I ₀ cos ² $\theta$

The average of cos ²$\theta$ = 1/2

Therefore ,

I _transmitted = (1/2) I ₀

The intensity changes by a factor of 0.5