Two polaroids P1 and P2 are placed in crossed positions. A third polaroid P3 is kept between P1 and P2 such that pass axis of P3 is parallel to that of P1 . How would the intensity of light (I2 ) transmitted through P2 vary as P3 is rotated ? Draw a plot of intensity ‘I2 ’ Vs the angle ‘θ’, between pass axes of P1 and P3 .
Use Malus law twice
for P1 and P3 I cos²x
for P3 and P2 I cos²(90-x)
you'll get I/4 sin²2x
for P1 and P3 I cos²x
for P3 and P2 I cos²(90-x)
you'll get I/4 sin²2x
