(a(i))[1]
Calculate the energy, in joules, that is equivalent to $5.75\,\text{MeV}$.
(a(ii))[2]
Calculate the number of $\alpha$-particles per second needed to produce $1.9\,\text{kW}$ of electrical power.
(b(i))[2]
Each plutonium-236 nucleus, when it disintegrates, emits one $\alpha$-particle. Plutonium-236 has a half-life of $2.8\,\text{years}$. Calculate the decay constant, in $\text{s}^{-1}$, of plutonium-236.
(b(ii))[4]
Use your answers in (a)(ii) and (b)(i) to determine the mass of plutonium-236 needed to generate $1.9\,\text{kW}$ of electrical power.
(c)[2]
The minimum electrical power required for the space probe is $0.84\,\text{kW}$. Calculate the time, in years, for which the sample of plutonium-236 in (b)(ii) will continue to supply enough power.