Light of intensity I0 passes through 4 ideal polarizing sheets. Unpolarized light enters the 1st sheet that has a horizontal transmission axis. Light continues to the 2nd sheet that has its transmission axis at 23 degrees with respect to the 1st sheet, then to the 3rd sheet that has its transmission axis at 42 degrees with respect to the 1st sheet then to the 4th sheet that has its transmission axis at 14 degrees with respect to the 3d sheet. The intensity of the emerging light as percentage of I0 is close to:

Respuesta :

Answer:

 I₄ / Io = 0.388 = 38.8%

Explanation:

For this exercise we will analyze the effect of having two depolarizers with an annulus between them, this is described by Malus's law

         I = Io cos² θ

where tea is the angle between the two polarizers.

For this case we must apply this law to each pair of polarizers.

The light that reaches the first polarizer is non-polarized light, therefore only the light that has polarization is transmitted in the direction of the depolarizer, which is horizontal.

          I₁ = I₀ / 2

this intnesidad reaches the second polarizer that has an angle of 23º with respect to the first polarizer

          I₂ = I₁ cos² 23

          I₂ = I₀ / 2 0.847

This light reaches the third polarizer, which has an angle of 42º with respect to the first polarized one.

Let's find the angle with respect to the 2nd polarizer

          θ = 42- 23

          θ = 19º

we apply the law of Malus

          I₃ = I₂2 cos 19

          I₃ = I₀ 0.847 / 2 0.9455

          I₃ = Io 0.4

This intensity of light reaches the fourth polarizer, with an angle of 14º with respect to the 3polarizer

          I₄ = Io 0.4 cos 14

          I₄ = Io 0.4 0.970

          I₄ = Io 0.388

to give this result as a percentage

          I₄ / Io = 0.388 = 38.8%