Unpolarized light is send through two polarizers. The first polarizer is oriente

Question

Unpolarized light is send through two polarizers. The first polarizer is oriented vertically, the 2nd polarizer is oriented at 45 degrees (clockwise) from the vertical. Which action below would increase the intensity of the light making it through the 2nd polarizer? Rotating the 2nd polarizer 15 degrees counter-clockwise Rotating the first polarizer 15 degrees clockwise Rotating the 2nd polarizer 15 degrees clockwise Rotating both polarizers 15 degrees clockwise Rotating both polarizers 15 degrees counter-clockwise. Rotating the first polarizer 15 degrees counter-clockwise

Explanation / Answer

Initially,

Intensity after passing through first polarizer will be

I1 = I0/2

Intensity after passing through second polarizer will be

I2 = I1*(cos 45 deg)^2 = (I0)*(1/sqrt 2)^2

I2 = I0/4 = 0.25*I0

Option A.

in this case angle between first and second polarizer will be = 45 - 15 = 30 deg

I2 = (I0/2)*(cos 30 deg)^2 = 3*I0/8 = 0.375*I0

Increase in intensity

Option B.

in this case angle between first and second polarizer will be = 45 - 15 = 30 deg

I2 = (I0/2)*(cos 30 deg)^2 = 3*I0/8 = 0.375*I0

Increase in intensity

Option C.

in this case angle between first and second polarizer will be = 45 + 15 = 60 deg

I2 = (I0/2)*(cos 60 deg)^2 = 1*I0/8 = 0.125*I0

decrease in intensity

Option D.

Angle between both polarizer will remain same in this case, since both polarizer moved with same angle in same direction.

I2 = 0.25*I0

Intensity remains same.

Option E.

Angle between both polarizer will remain same in this case, since both polarizer moved with same angle in same direction.

I2 = 0.25*I0

Intensity remains same.

Option F.

in this case angle between first and second polarizer will be = 45 + 15 = 60 deg

I2 = (I0/2)*(cos 60 deg)^2 = 1*I0/8 = 0.125*I0

decrease in intensity

Correct option will be A and B.

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.