A monochromatic laser beam of wavelength 632nm in air (where the speed of light is 3.00×108ms−1) enters a flat slab of crown glass in which light travels at 2.00×108ms−1. The beam is incident perpendicular to the surface so that refraction angles need not be considered.
(a) Calculate the wavelength of the laser light while it is inside the glass slab. Express your result in nanometres.
(b) The slab is 1.50mm thick. Determine the number of complete wavelengths that fit exactly within the thickness of the glass when the beam is fully inside the slab.
(c) As the light exits the far side of the slab back into air, describe qualitatively what happens to its speed, wavelength, and frequency. Explain the physical reason for any quantity that remains unchanged.