Question

Two beams, A and B, of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid .The two beams appears equally bright when the polaroid is rotated by an angle of 300 from the position where beam A has maximum intensity (ie. Beam B has zero intensity).If the initial intensities of the two beams are $I_A$ and $I_B$ respectively, then $\frac{I_A}{I_B}$ equals:

• A. 1
• B. $\frac{1}{3}$
• C. 3
• D. $\frac{3}{2}$

Answer 1

$I_{A}co{s}^{2}30=I_{B}co{s}^{2}60\frac{I_A}{I_B}=\frac{1}{3}$