Chapter 35.11, Problem 1EE

CONCEPTUAL EXAMPLE 35–14

Three Polaroids. We saw in Fig. 35–36 that when unpolarized light falls on two crossed Polaroids (axes at 90°), no light passes through. What happens if a third Polaroid, with axis at 45° to each of the other two, is placed between them (Fig. 35–38a)?

EXERCISE E How much light would pass through if the 45° polarizer in Example 35–14 was placed not between the other two polarizers but (a) before the vertical (first) polarizer, or (b) after the horizontal polarizer?