.1 Assuming that the hydrogen atom is spherical, by what factor is its volume greater when in its first excited state than when in its ground state?

2. What experimental evidence supported Bohr's postulate concerning the existence of discrete energy levels in the hydrogen atom?

3. Describe the change in each of the following quantities as an electron passes from one Bohr orbit to the next higher energy orbit:

a) speed

b) orbital radius

c) energy

d) de Broglie wavelength

4. According to the Bohr theory, what is the radius of the second excited state of the hydrogen atom?

5. An electron and a proton are accelerated to equal kinetic energies, attaining speeds low enough to keep relativistic effects negligible. Find the ratio of their de Broglie wavelengths.

6. The kinetic energy of a certain particle is equal to the energy of a photon. The particle moves at 5.0% the speed of light. Find the ratio of the photon wavelength to the de Broglie wavelength of the particle.