Find the wavelength of the radiation emitted when an electron in a hydrogen atom falls from the third orbit to the second. Take the Rydberg constant as 1.097 × 10⁷ m⁻¹.

Define mass defect and binding energy, and explain why the binding energy per nucleon curve peaks near iron.

The half-life of a radioactive nuclide is 4 days. What fraction of a sample remains after 16 days, and what is its decay constant?

Calculate the energy of an electron in the second orbit of a hydrogen atom.

State the postulates of Bohr's model of the atom.

State two limitations of Bohr's model of the atom.

State Kirchhoff's two laws and say what conservation principle each expresses.