(a) Explain the following, illustrating your answer with one example in each case: (i) nuclear fusion: (ii) nuclear fission: (iii) radiation hazards. (b) St...

Answer Details

(a)(i) Nuclear fusion: the joining together of two light atomic nuclei to form a single heavier nucleus, with the release of a large amount of energy. Example: the fusion of hydrogen (deuterium) nuclei to form helium in the Sun.

(a)(ii) Nuclear fission: the splitting of a heavy atomic nucleus into two lighter nuclei of comparable mass, accompanied by the release of neutrons and a large amount of energy. Example: the splitting of a uranium-235 nucleus when it captures a slow neutron.

(a)(iii) Radiation hazards: the harmful effects that nuclear radiations (alpha, beta, gamma) have on living tissue. Example: exposure to gamma rays can damage or kill body cells and cause cancer or genetic mutations.

(b) Two advantages of fusion over fission:

• Fusion produces more energy per unit mass of fuel and its fuel (hydrogen) is cheap and abundant.
• Fusion produces little or no long-lived radioactive waste, so it is cleaner.

In spite of these, fusion is not normally used for power generation because it requires extremely high temperatures (millions of degrees) and pressures to bring the nuclei close enough to fuse, and no ordinary container can withstand or confine such conditions economically.

(c) Given \(I=30\sin100\pi t\), compare with \(I=I_o\sin(2\pi f t)\).

(i) Frequency: \(2\pi f=100\pi\Rightarrow f=50\,\text{Hz}\).

(ii) Peak value: \(I_o=30\,\text{A}\).

(iii) r.m.s. value: \(I_{rms}=\dfrac{I_o}{\sqrt{2}}=\dfrac{30}{\sqrt{2}}=21.2\,\text{A}\).