AQA a level physics paper 1 100% SOLUTIONS REVISED 2023//2024

What is meant by work function (2) - ANSWER Minimum energy required by an electron to escape from (1) a metal surface (1) What is meant by ionisation energy? (2) - ANSWER Minimum energy required to remove an electron from an atom (1) from the ground state (1) 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) 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) What is meant by the ground state? - ANSWER The lowest energy state of an atom Explain the difference between excitation and ionisation (2) - ANSWER An electron