A point source S emits unpolarized light uniformly in all directions. At two points A and B , the ratio r=I_A / I_B of the intensities of light is 2. If a set of two polaroids having 45^ angle between their pass-axes is placed just before point B , then the new value of r will be ______
A. A
\(I 1 l^2 \) Where I: distance from point source. \( aligned & I_A I_B = I_B^2 I_A^2 =2 \\ & I_B= 2 I_A . aligned \) Also, due to polaroids: \( aligned & I_B^ = I_B 2 ^2 45^ = I_B 4 \\ & I_B^ = I_B 4 (2) \\ & Ratio becomes 4 times. \\ & r_ new =8 aligned \)
Related: Physics — Wave Optics · All PYQ Banks