Question

A horizontal beam of light of intensity 25 W/m2 is sent through two polarizing sheets. The polarizing direction of the first makes a 15° angle with that of the second. Suppose that the initial beam is unpolarized. What then is the intensity of the transmitted light? A. 7.2 W/m2 B. 11.7 W/m2 C. 12.1 W/m2 D. 23.3 W/m E. 24.1 W/m

Answer 1

option (B)

Step-by-step explanation:

Intensity of unpolarised light, I = 25 W/m^2

When it passes from first polarisr, the intensity of light becomes

`I'=(I_(0))/(2)=(25)/(2)=12.5 W/m^(2)`

Let the intensity of light as it passes from second polariser is I''.

According to the law of Malus

`I'' = I' Cos^(2)\theta`

Where, θ be the angle between the axis first polariser and the second polariser.

`I'' = 12.5* Cos^(2)15`

I'' = 11.66 W/m^2

I'' = 11.7 W/m^2