An Ionic Crystal Figure shows eight point charges arranged at the corners of a cube with sides of length d. The values of the charges are +q and -q, as shown. This is a model of one cell of a cubic ionic crystal. In sodium chloride (NaC1), for instance, the positive ions are Na + and the negative ions are C1-.
(a) Calculate the potential energy U of this arrangement. (Take as zero the potential energy of the eight charges when they are infinitely far apart.)
(b)In part (a), you should have found that U

Transcribed Image Text:

+9 +g b- +g