Explanations/state questions to revise Flashcards
Name the boson associated with the electromagnetic force
Photon
State what is meant by the term coherent
The waves from the two sources have a constant phase relationship (and have the same frequency, wavelength, and velocity).
Explain why the photoelectric effect provides evidence for the particle nature of light. (1)
Each photon contains a fixed/discrete amount of energy. OR Each photon removes one electron.
State two features of the Bohr model of the atom
A (central) positively charged nucleus OR A (central) nucleus containing protons (and neutrons). (Negatively charged) electrons in (discrete) energy levels/shells (orbiting the nucleus, not radiating energy.) When an electron moves from one state to another, the energy lost or gained is done so ONLY in very specific amounts of energy. Each line in a spectrum is produced when an electron moves from one energy level/orbit/shell to another
State the type of particle that is made of a quark/antiquark pair. (1)
Meson
State the name given to the group of matter particles that contains quarks and leptons.
Fermion
What is the equivalent unit of Farads?
Coulombs per Volt
The W-boson is the force-mediating particle associated with the decay of kaons. Name the fundamental force involved in the decay of kaons. (1)
Weak nuclear force
- A student carries out an experiment to investigate the charging of a capacitor, using the circuit shown. The variable voltage supply is set at 12 V.
Describe how the results of this experiment are obtained and used to show how the voltage across the capacitor varies with time while the capacitor is charging. (2)
Close the switch and) take readings on voltmeter at (regular) time intervals (1) Plot a graph of voltage against time (1)
- Explain how a line emission spectrum is produced. (2)
If an electron is in an excited state it can return to a lower energy level. When it does this, it emits a photon. (1) Different transitions produce different lines/ frequencies (of photons). (1) Accept: When an electron drops down a level it releases energy.
- Explain why some of these lines appear brighter than others. (2) (Follows line emission spectra question)
(For the brighter lines) more electrons are making those transitions (per second). (1) (Therefore), there are more photons (per second) emitted (of that specific energy and so produce brighter lines). (1)
