The diagram shows three of the energy levels in an isolated hydrogen atom. The lowest energy level is known as the ground state.
In the diagram, each energy level is labelled with its 'principal quantum number' $n$. Use the energy level diagram to show that the energy $E$ of an energy level is inversely proportional to $n^{2} .$
Important Questions on Quantum Physics
Explain how the photoelectric effect gives evidence for the wave-particle duality of electromagnetic radiation.
State what is meant by the de Broglie wavelength of an electron.
The diagram shows the principles of an electron tube used to demonstrate electron diffraction.
Calculate the kinetic energy $E$ (in joules) of the electrons incident on the graphite film.
The diagram shows the principles of an electron tube used to demonstrate electron diffraction.
Show that the momentum of an electron is equal to $\sqrt{2 E m_{e}}$ where $m_{\mathrm{e}}$ is the mass of an electron, and hence calculate the momentum of an electron. $\left(m_{\mathrm{e}}=9.11 \times 10^{-31} \mathrm{~kg}\right)$
