A small charged sphere has a mass of 0.05 kg and a charge of -6.5x10−5 −
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C. A second small charged sphere has a mass of 0.07 kg and a charge of -3.6x10−5
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C. What electrostatic force exists between them if they are 22cm (0.22m) apart? Is the force attractive or repulsive?

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