Вопрос
6.Two polarizers are oriented at 48^circ to each other and plane -polarized light is incident on them.If only 35% of the light gets through both of them, what was the initial polarization direction of the incident light ()
Решения
4.2
(270 Голоса)
Эмир
Экспертная проверка
профессионал · Репетитор 6 лет
Ответ
To find the initial polarization direction of the incident light, we need to consider the Malus's law, which relates the intensity of light after passing through a polarizer to the angle between the polarization direction of the incident light and the axis of the polarizer.Malus's law is given by:
where:-
is the intensity of the light after passing through the polarizer,-
is the initial intensity of the light,-
is the angle between the polarization direction of the incident light and the axis of the polarizer.In this case, we are given that only 35% of the light gets through both polarizers. This means that the intensity of the light after passing through both polarizers is 35% of the initial intensity.Let's denote the initial polarization direction of the incident light as
. The light first passes through a polarizer oriented at an angle of
to the incident polarization direction, and then through a second polarizer oriented at an angle of
to the first polarizer.Using Malus's law for the first polarizer, we have:
Using Malus's law for the second polarizer, we have:
Substituting the expression for
from the first equation into the second equation, we get:
We are given that
, so we can substitute this into the equation:
Dividing both sides by
, we get:
To find the value of
, we need to solve this equation. Taking the square root of both sides, we get:
Dividing both sides by \( \cos(48^\circ) \), we get:
Finally, taking the inverse cosine of both sides, we get:
Calculating this value, we find that
is approximately
. Therefore, the initial polarization direction of the incident light was
relative to the axis of the first polarizer.