Paper 2 Wave-Particle Duality Answers

Q1 Electron de Broglie Wavelength

1. $E=eV=(1.60\times 10^{-19})(150)=2.40\times 10^{-17}\mathrm{J}$. [1]
2. $p=\sqrt{2mE}=\sqrt{2(9.11\times 10^{-31})(2.40\times 10^{-17})}=6.61\times 10^{-24}\mathrm{kg}\mathrm{m}{\mathrm{s}}^{-1}$. [2]
3. $\lambda =h/p=6.63\times 10^{-34}/6.61\times 10^{-24}=1.00\times 10^{-10}\mathrm{m}$. [2]

Q2 Evidence Map

1. Photoelectric effect or Compton scattering. [1]
2. Electron diffraction. [1]
3. Quantum entities are described by models that predict different experimental outcomes; wave-like propagation/interference and particle-like detection/energy transfer are both real features in appropriate contexts. [3]

Q3 Photon Momentum

1. $p=h/\lambda =6.63\times 10^{-34}/(5.00\times 10^{-7})=1.33\times 10^{-27}\mathrm{kg}\mathrm{m}{\mathrm{s}}^{-1}$. [2]
2. $E=hc/\lambda =(6.63\times 10^{-34})(3.00\times 10^8)/(5.00\times 10^{-7})=3.98\times 10^{-19}\mathrm{J}$. [2]
3. Both energy and momentum increase. [1]