Page 515 - Physics Coursebook 2015 (A level)

Chapter 31: Nuclear physics
4 The equation shows the radioactive decay of radon-222. 222Rn → 218Po + 4α + γ
86 84 2
Calculate the total energy output from this decay and state what forms of energy are produced. [6]
(Mass of 222Rn = 221.970u, mass of 218Po = 217.963u, mass of 4α = 4.002u; 86 84 2
1 u is the unified atomic mass unit = 1.660 × 10−27 kg.)
(Hint: find the mass defect in u, then convert to kg.)
5 A carbon-12 atom consists of 6 protons, 6 neutrons and 6 electrons. The unified atomic mass unit (u)
isdefinedas 1 themassofthecarbon-12atom. 12
Calculate:
a the mass defect in kilograms [2]
b the binding energy [2]
c the binding energy per nucleon. [2]
(Mass of a proton = 1.007 276 u, mass of a neutron = 1.008 665 u, mass of an electron = 0.000 548 u.)
6 The fusion reaction which holds most promise for the generation of electricity is the fusion of tritium 31H and deuterium 21H. The equation below shows the process:
31H+ 21H→ 42He+ 1H
Calculate:
a the change in mass in the reaction [3]
b the energy released in the reaction [2]
c the energy released if one mole of deuterium were reacted with one mole of tritium. [2]
(Mass of 31H = 3.015500u, mass of 21H = 2.013553u, mass of 42He = 4.001506u, mass of 1H = 1.007276u.)
7 The initial activity a sample of 1 mole of radon-220 is 8.02 × 1021 s−1. Calculate:
a the decay constant for this isotope [3]
b the half-life of the isotope. [2]
8 Figure 31.14 Shows the count rate recorded when a sample of the isotope indium-116 decays. 160
120 80 40
00 10 20 30 40 50 60 70 Time / s
Figure 31.14 For End-of-chapter Question 8.
a Use the graph to find the half-life of the isotope. [2]
b Calculate the decay constant. [2]
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Count rate / Bq