1. Design a sodium vapor lamp that emits light at l = 590 nm with a bulb temperature of 540 K. The Na wavelength from the vapor in the bulb must penetrate the glass, but the bulb must stay hot. It is more efficient if the longer wavelengths (i.e. heat ) are reflected back into the interior of the bulb. Assume that the bulb container has layers of transparent glass, with a semiconductor reflective coating. Design the required electron concentration for proper operation. Assume that the contribution to the permittivity of bound electrons is 1.
2. Design a coating for windows in a house that lets in sunlight (effective source temperature of 6000 K) with wavelengths in the range from 0.3 micron to 1.5 micron, as described in class. The room temperature within the house is 300 K and the window coating of conductive glass should reflect the heat wavelengths back into the house. Design an electron concentration of the coating to optimize the energy efficiency of the house.
3. For a lightly doped sample of Si with resistivity of 1 Ohm-cm, and an applied current density of J = 1000 Amp/cm2, compare the electric field components attributed to the inertial and the Ohmic contributions. What is the required transient pulse dJ/dt that is needed to make the two field components equal? Can this transient current value be reasonably achieved in the lab with standard equipment? Explain.
4. Look up data for the plasma frequency of copper (Cu). Does it agree with your expectations based on the discussions in class? For data, use your favorite handbook or acquaint yourself with some from the library.
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