An unpolarised beam of intensity I0 is incident on a pair of nicols making an angle of 60° with each other. The intensity of light emerging from the pair is

Question

An unpolarised beam of intensity I0 is incident on a pair of nicols making an angle of 60° with each other. The intensity of light emerging from the pair is (A) I0 (B) I0 / 2  (C) I0 / 4  (D) I0 / 8

Tardigrade Admin · Accepted Answer

After passing from first nicol the intensity will be reduce by

50%

I^{'} = \frac{I _{0}}{2}

Then it will pass from second nicol
According to Malus' law

I = I_{0} cos^{2} θ = I_{0} (cos^{2} 6 0^{\circ})

I^{'} \times (\frac{1}{2})^{2} = \frac{I ^{'}}{4} = \frac{I _{0}}{8}

Q. An unpolarised beam of intensity $I_{0}$ is incident on a pair of nicols making an angle of $6 0^{\circ}$ with each other. The intensity of light emerging from the pair is

$I_{0}$

$I_{0} /2$

$I_{0} /4$

$I_{0} /8$

After passing from first nicol the intensity will be reduce by $50%$
$I^{'} = \frac{I _{0}}{2}$
Then it will pass from second nicol
According to Malus' law
$I = I_{0} cos^{2} θ = I_{0} (cos^{2} 6 0^{\circ})$
$I^{'} \times (\frac{1}{2})^{2} = \frac{I ^{'}}{4} = \frac{I _{0}}{8}$

Q. An unpolarised beam of intensity I0​ is incident on a pair of nicols making an angle of 60∘ with each other. The intensity of light emerging from the pair is

I0​

I0​/2

I0​/4

I0​/8