Some charged particles are suspended inside a hollow metal object by supports made of a material that is an electrical insulator. The metal object has charge +q distributed over its outer surface and charge ?2q distributed over its inner surface.

A. How much charge is suspended in the cavity?

B. What is the charge on the object? (Hint: What is the electric field a very large distance r from the center of the object?)

An electron is trapped at a defect in a crystal. the defect may be modeled as a one-dimensional, rigid-walled box of width 1.00 nm. (a) sketch the wavefunctions and probability densities for the n 1 and n 2 states. (b) for the n 1 state, nd the probability of nding the electron between x1 0.15 nm and x2 0.35 nm, where x 0 is the left side of the box. (c) repeat (b) for the n 2 state. (d) calculate the energies in electron volts of the n 1 and n 2 states