Consider one particle confined to a cube of side L; the concentration in effect is n = l/L3. Find the kinetic energy of the particle when in the ground orbit. There will be a value of ht concentration for which this zero-point quantum kinetic energy is equal to the temperature τ. (At this concentration the occupancy of the lowest orbital.) show that the concentration n0 thus defined is equal to the quantum concentration nQ defined by (63), with in a factor of the order of unity.