Chapter 33, Problem 33.56P

A thin beam of white light is directed at a flat sheet of silicate flint glass at an angle of 20.0° to the surface of the sheet. Due to dispersion in the glass, the beam is spread out in a spectrum as shown in Fig. P33.56. The refractive index of silicate flint glass versus wavelength is graphed in Fig. 33.17. (a) The rays a and b shown in Fig. P33.56 correspond to the extreme wavelengths shown in Fig. 33.17. Which corresponds to red and which to violet? Explain your reasoning. (b) For what thickness d of the glass sheet will the spectrum be 1.0 mm wide, as shown (see Problem 33.54)?

Figure P33.56