Physics (AS & A Level) · May / June 2016 · Paper 23 · Question 8

α-particle is 2 protons and 2 neutrons;

β+-particle is positive electron/positron α-particle has charge +2e;

β+-particle has +e charge α-particle has mass 4u;

β-particle has mass (1/2000)u α-particle made up of hadrons;

β+-particle a lepton any three [3]

ν β 0 0 0 1 1 0 1 1 n p + + → all terms correct all numerical values correct (ignore missing values on ν) [2]

1. proton: up, up, down / uud 2. neutron: up, down, down / udd [2]

up quark has charge +2 / 3 (e) and down quark has charge –1 / 3 (e) total is +1 (e) [1]