(pressure and energy density of electromagnetic radiation) consider the electromagne- tic radiation (photon gas) contained in an edge box lg, ly and l2. as an image moves with the speed of light, it is a relativistic particle. therefore, its energy e is related to its moment hk through: к3)12 кз. € — сhk — сh(к- (2) (a) use this relation to calculate the force fr exerted by a photon vessel when the photon is in a state r specified by nx, ny, nz. on the right wall of the (b) using the average energy of a photon. use the symmetry requirement k2 k2 the radiation is in equilibrium with the walls of the enclosure expression for the average force f as a function of simple average, deduce an a k2, when (c) from here show that the average pressure p exerted on the walls by radiation is given by: 1 (3 where uis the electromagnetic energy of the radiation per unit volume.