HSC Physics Atoms to Universe

  1. Atoms emit discrete wavelengths of light. Explain why a heated iron bar changes colour as its temperature changes.
  2. The energy of an electron in the ground state of a hydrogen atom is -13.6 eV. (a) How can an electron have a negative energy? (b) What is the energy of an electron in the first excited state? (c) determine the value of the three longest wavelengths in the Balmer series for hydrogen.
  3. A proton moves at a constant speed of 0.90c. The proton moves once around the tube of a particle accelerator of circumference 20.0 km. (a) What are the momentum and the energy of the proton in the laboratory reference frame? (c) What is the distance travelled by the proton in its own reference frame?

  4. more to come