Two polaroids A and B are kept with their transmissions axes at an angle 0 with respect to one another. If the transmitted intensity of light It = 0.75 I0 where I0 is the intensity of light incident on the system. The θ is

Question

Two polaroids A and B are kept with their transmissions axes at an angle 0 with respect to one another. If the transmitted intensity of light It = 0.75 I0 where I0 is the intensity of light incident on the system. The θ is (A) 30°  (B) 45°  (C) 60°  (D) 90°

Tardigrade Admin · Accepted Answer

Here, It = 0.75 : I0 ......(i) Intensity of transmitted light is given by It = I0 : cos2 θ ... (ii) Comparing eqn. (i) with (ii), cos2 θ = 0.75 = (3/4) cos θ = (√3/2) = cos 30° or θ = 30°

Q. Two polaroids $A$ and $B$ are kept with their transmissions axes at an angle 0 with respect to one another. If the transmitted intensity of light $I_{t} = 0.75 I_{0}$ where $I_{0}$ is the intensity of light incident on the system. The $θ$ is

$3 0^{\circ}$

$4 5^{\circ}$

$6 0^{\circ}$

$9 0^{\circ}$

Here, $I_{t} = 0.75 I_{0}$ ......(i)
Intensity of transmitted light is given by $I_{t} = I_{0} cos^{2} θ$ ... (ii)
Comparing eqn. (i) with (ii),
$co s^{2} θ = 0.75 = \frac{3}{4}$
$cos θ = \frac{3}{2} = cos 3 0^{\circ}$ or $θ = 3 0^{\circ}$

Q. Two polaroids A and B are kept with their transmissions axes at an angle 0 with respect to one another. If the transmitted intensity of light It​=0.75I0​ where I0​ is the intensity of light incident on the system. The θ is

30∘

45∘

60∘

90∘