A hypothetical atom has two energy levels, with a transition wavelength between them of 580 nm. In a particular sample at 300 K, $4.0\cdot {10}^{20}$ such atoms are in the state of lower energy. (a) How many atoms are in the upper state, assuming conditions of thermal equilibrium? (b) Suppose, instead, that $3.0\cdot {10}^{20}$ of these atoms are “pumped” into the upper state by an external process, with $1.0\cdot {10}^{20}$ atoms remaining in the lower state. What is the maxi-mum energy that could be released by the atoms in a single laser pulse if each atom jumps once between those two states (either via absorption or via stimulated emission)?