Which statement should he place in the region marked X? It does not involve touching the objects together. The objects develop opposite charges. Electrons move between objects. The objects have the same charge.

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.