AQA A level physics paper 1 Q&A

AQA A level physics paper 1 Q&A 1-What is meant by work function (2) - answer-Minimum energy required by an electron to escape from (1) a metal surface (1) 2-What is meant by ionisation energy? (2) - answer-Minimum energy required to remove an electron from an atom (1) from the ground state (1) 3-Why do emitted electrons have a kinetic energy that varies up to a maximum value? (4) - answer-Energy of a photon is fixed/constant (1) Energy is required for electrons to overcome work function ø (1) Electrons deeper into/below the surface of the metal require more energy to overcome work function and therefore have less KE(1) Maximum KE = Energy of photon - work function ø (1) 4-Explain how (bright ring) diagram is evidence of the wave-particle duality of electrons? - answer-Diffraction pattern maxima/minima (bright and dark areas) (1) Diffraction is a property of waves- proves wave-behaviour of electrons (1) 5-What is meant by the ground state? - answer-The lowest energy state of an atom 6-Explain the difference between excitation and ionisation (2) - answer-An electron receives a discrete amount of energy for BOTH (1) Excitation promotes an electron to a higher energy level Ionisation is when an electron receives enough energy to leave the atom 7-Explain why only photons of certain frequencies cause excitation (4) - answer-discrete energy levels (1) Electrons need to absorb a DISCRETE amount of energy to move to a higher energy level (1)...