Binding energy, fusion and fissionEdexcel International A Level Physics: Mind map

Exam questions on Binding energy, fusion and fission

1. A student is analysing the helium-4 nucleus, which contains 2 protons and 2 neutrons. She is given the following data: mass of a proton = 1.00728 u; mass of a neutron = 1.00867 u; mass of a helium-4 nucleus = 4.00151 u.
   Calculate the mass deficit of the helium-4 nucleus, in u.2 marks
2. A nuclear physicist is converting between units for a nucleus whose mass deficit is 0.0580 u. Use: 1 u = 1.66 × 10⁻²⁷ kg; c = 3.00 × 10⁸ m s⁻¹; 1 MeV = 1.60 × 10⁻¹³ J.
   Calculate the binding energy of the nucleus in MeV.2 marks
3. The binding energy per nucleon of the nuclei rises steeply from about 1 MeV for hydrogen-2 to about 7 MeV for helium-4, reaches a maximum of about 8.8 MeV near iron-56, and then falls slowly to about 7.6 MeV for uranium-235. A uranium-235 nucleus can absorb a neutron and split into two fragments of medium mass, each with a binding energy per nucleon of about 8.5 MeV.
   Explain, with reference to the binding energy per nucleon curve, why energy is released when two light nuclei such as hydrogen-2 undergo fusion to form helium-4.3 marks