(6.0.20) Shown below is a stack of three polarizers. The transmission axis of the finst polarizer is vertical. The transmission axis of the second polarizer makes angle o with the vertical. The transmission axis of the third polarizer makes angle 70 with the vertical. Unpolarized light of intensity la traveling from left to right is incident on the first polarizer. (a) Sketch the polarization of the light emerging from each of the three polarizers. (b) Find an expression for the intensity of the light emerging from the third polarizer. This expression should be in terms of la and o. (c) Show that there is a unique value of o which maximizes the intensity of the light which emerges from the third polarizer. Do not simply state a result you believe to be correct. You must prove that this is a true maximum. (d) For the value of o that you found in (c), determine the intensity of the light emerging from the third polarizer, given that lo = 0.8 W/em. propagation direction 70