Ahorizontal 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

option (B)

Explanation:

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

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

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

According to the law of Malus

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

I'' = 11.66 W/m^2

I'' = 11.7 W/m^2

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

vapour or gas assuming atmospheriv pressure