Chapter 24, Problem 56P

To determine

The angle of one Polaroid that subsequently reduces the intensity of light by half.

Answer to Problem 56P

  $45°$ .

Explanation of Solution

Given:

The light pass through two aligned Polaroids is maximum.

Formula used:

It is known that: $\text{I}={\text{I}}_{\text{0}}{\text{cos}}^{\text{2}}\text{θ}$

Where,

  $\text{I}$ is intensity after passing first Polaroid.

  $I_0$ is intensity after passing second Polaroid.

  $\theta$ is an angle.

Calculation:

  $I$ is the intensity passed by first Polaroid.

The intensity $I_0$ after passing second Polaroid.

For reducing the intensity to the half,

  $\text{I}={\text{I}}_{\text{0}}{\text{cos}}^{\text{2}}\text{θ=}\frac{{\text{I}}_{\text{0}}}{2}$

  $\therefore \text{θ}=45°$

Conclusion:

The required angle is $45°$ .