IB Physics HL E.4.1 Fission energy release Question Bank

Practise IB Physics SL/HL E.4.1 by applying fission energy release concepts to exam-style physics questions.

Exam points

identify the relevant physical quantity, model or diagram
apply the correct equation and units to the evidence
justify the result using conservation laws, fields or energy relationships

[Maximum number: 4]

(a)

A nuclear power station uses U-235 as fuel. Assume that every fission reaction of U-235 gives rise to 180 MeV of energy.

[ 4 ]

(i)

Estimate, in $\mathrm{Jkg}^{-1}$ , the specific energy of U-235.

[ 2 ]

see «energy = » $180 \times 10^{6} \times 1.60 \times 10^{-19}$ AND «mass =» $235 \times 1.66 \times 10^{-27}$ $7.4 \times 10^{13} \ll \mathrm{~J} \mathrm{~kg}^{-1} \gg$

(ii)

The power station has a useful power output of 1.2 GW and an efficiency of 36 %. Determine the mass of U-235 that undergoes fission in one day.

[ 2 ]

$\text { energy produced in one day }=\frac{1.2 \times 10^{9} \times 24 \times 3600}{0.36}=2.9 \times 10^{14} \ll \mathrm{~J}>\text { }$

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E.4.1—Fission energy release question 1

Question (a)

Question (i)

Question (ii)