An atomic beam is intended to function with (a) cadmium, (b) mercury. The source is an oven maintained at 380K with a small slit of dimensions 1.0cm x 1.0 x 10-3cm. Explain the vapor pressure of cadmium is 0.13 P and that of mercury is 12 Pa at this temperature. Explain what is the atomic current the number of atoms per second in the beams?