how do I calculate intensity of beam after polarization?

Question

anonymous · Answer

The intensity after passing through the first polaroid is I/2

where I is the Original intensity.

after passing through the 2nd polaroid the intensity is $$I \cos ^{2}\phi/2$$

[Malus Law]

anonymous · Answer

where phi is the angle the 2nd polaroid makes with the first.

anonymous · Answer

half the intensity is theta/2? I haven't seen that before can you explain why its theta/2

anonymous · Answer

lozoot93: thanks for your answer!

Romero: half the intensity is the Original intensity (I) divided by 2 as shown in the equation; the theta belongs to the cos^2