AS Physics Unit 1 1 Matter and Radiation Ks5 AS Physics AQA 2450 Mr D Powell

Unit 1 Chapter 1 Worked Exam Questions

1) -1 particle particle anti-particle +1 B particle anti-particle +1 B They have opposite charge / spin thus in a magnetic field will curve in different directions. They are losing kinetic energy as if an orbiting satellite which starts to graze the atmosphere of earth. The beta particles passing through the lead plate slowed down and curved one direction this one curved the other way.

2) P = 90 N = 139 E = 90 X = 90 Y = 227, 228, 230, 231, 234 (any value 212 -252) Z = 90

3) 18, 19 2x 1.6 x 10-19C = +3.2 x 10-19C neutron, electron p + n = 37 x 1.67x10-27 = 6.179x10-26 electrons = 16 x 9.11x-31 = 1.4576x10-29 (100 x e)/(p + n) = 0.02%

4) P = 14, N = 14, E = 28 B) same e and p, different number of neutrons often decay to become more stable 137-55 = 82 92 x -1.6 x10-19C / 236 x 1.67x-27 = 37.3 x 106C/kg X = 236 – 137 – 4 = 95

5) 225 88

6)

6) Answer i) alpha particle is 2 protons & 2 neutrons. Is deflected strongly by a magnetic or electrical field. a.m.u 4 charge of +2 x 1.6 x 10-19C and can be detected due to its charge and ionising power in a bubble / cloud chamber. b) i neutron converts to a proton via weak interaction and the W- gauge boson. The gauge boson travels a very short distance (1x 10-18) then quickly decays into a - particle (electron) and an electron antineutrino. ii)

7)

7) Answer

8) A) Electron They annihilate into energy of the order of that originally contained in the two particles. 0.51MeV x 2 = 1.02MeV 1.02 x 106eV x 1.6 x 10-19J/eV = 1.63 x 10-13J (1eV = 1.6x10-19J)

9) A) The particles annihilate to pure energy Energy is conserved from total energy before. So the energy of the collision is part kinetic and part rest mass i.e. E=mc2 for each particle. B) There could be more particles produced, more of the same particle, particles of different energies

10) + W+ boson or force carrier but the force is called the “weak interaction” is the method of transfer. This particle transfers the electromagnetic force, energy and momentum. Process is called “electron capture”. Diagram show shown the p turns to neutron, and e- to a ve . The diagram below shows an example. Where an atom experiences “electron capture”.

11)

12) Describe what happens in pair production and give one example of this process. 3 marks…