Question

Low-energy electrons are accelerated between electrodes in a tube filled with a gas in the Franck-Hertz apparatus represented above. A plot of current collected versus accelerating voltage is also shown. The data provide evidence for which of the following? (A) Electronic energy losses due only to elastic collisions (B) Excitation energies of the gas atoms of 4.9, 9.8, and 14.7 eV C) Excitation energy of the gas atoms of 4.9 eV only (D) Atomic energy levels of -4.9, -9.8, and -14.7 eV (E) Atomic energy levels of-4.9 and -9.8 eV only

Answer 1

the given data provided for the excitation energies of the gas atoms of 4.9, 9.8 and 14.7 eV.

hence option B is correct

the quantized nature of energy levels are confirmed by the frank hertz experiment.  The gas atom excited by the electron and electron loses energy. it is inelastic collisions