IB Physics HL E 4 1 Fission Energy Release Questions

Calculate HL fission energy release from binding-energy data, mass and number of uranium nuclei, including specific energy per kilogram.

Exam points

Energy is released in spontaneous and neutron-induced fission.

[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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IB Physics HL E 4 1 Fission Energy Release Questions question 1

Question (a)

Question (i)

Question (ii)