Select the correct answer Alight wave travels at a speed of 3.0 x 108 meters/second. If the wavelength is 7.0X107 meters, what is the frequency of the wave?

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.