1. 1a) A crest from one source arrives at the same time as a trough from the other and destructively interfere with each other. 1b) p.d. = 0.5 λ = 0.4 m λ = 0.8 m. 2) n λ = d sinθ

2. 3a) v glass = v air /ŋ = 3 x 10 8 / 1.5 = 2.0 x 10 8 ms -1 b) λ glass = λ air / 1.5 = 450 / 1.5 = 300 nm. Frequency is unchanged critical angle total internal reflection will take place

3. 4)

4. The laser beam is not a point source

5. 5a) The photons of UV light have sufficient energy to eject an electron but the photons of light that make up white light have insufficient energy to eject electrons. b) Work function is the minimum energy required to eject an electron from the metal.

7. 7)E = m.c2 E = 0.250 x (3 x 10 8 )2 E = 2.25 x 10 16 J 8) Fission : break up a large nucleus into smaller fragments with the release of energy Fusion : joining of two small nuclei to form a larger one with the release of energy.

8. Fermions : ( have a half integer spin ) these are quarks and their composite particles such as protons and neutrons and Leptons, electrons, muons and Tau particles. Hadrons are made from quarks, they have integer charge, baryons are made from 3 quarks and mesons are made from one quark and one antiquark Strong force : gluons Weak force W and Z Bosons Electromagnetic force : photons And Gravity force : Gravitons

9. Images

10. The alpha particle will rotate in an anticlockwise circle The beta particle would rotate in a clockwise circle.

11. The electric field does work on the alpha particle, its EK increases. Ek = QV Ek increase = 2 x1.6x10 -19 x 5 x10 3 = 1.6x10 -15 J Ek = 0.5 m v 2 V 2 = 2 x 1.6 x10 -15 / m = 3.2x10 -15 / 6.696x10 -27 = 4.779x10 11 V = 6.91x10 5 ms -1. Electric fields are used to accelerate the particles and magnetic fields are used to guide them.