Answer
See below.
Work Step by Step
If the incoming polarized light is polarized, say, horizontally, and the filter's transmission axis is also oriented horizontally, all the light gets through.
On the other hand, if the filter is aligned perpendicular to the polarization of the light, i.e., vertically, none of the light gets through.
At angles in between, a fraction (varying from 0-100 percent) of the light gets through. The polarized light can be "resolved" (like a vector) into horizontal and vertical components.
This is discussed on pages 555-556. Figure 29.32, an analogy with ropes passing through a pair of picket fences, is helpful in understanding this concept.
