Question 1
Paper 2Easy9 marksOne possible neutron-induced fission reaction of uranium-235 is
²³⁵₉₂U + ¹₀n → ¹⁴¹₅₆Ba + ⁹²₃₆Kr + 3 ¹₀n
The following rest masses are available:
| Particle or atom | Rest mass / u |
|---|---|
| ²³⁵U | 235.043930 |
| ¹n | 1.008665 |
| ¹⁴¹Ba | 140.914411 |
| ⁹²Kr | 91.926156 |
(a)[2]
Distinguish between spontaneous fission and neutron-induced fission.
(b)
For the reaction and data above, use 1 u c² = 931.5 MeV and 1 MeV = 1.60 × 10⁻¹³ J.
(i)[3]
Determine the energy released in the reaction, in MeV.
(ii)[2]
Using your answer to (b)(i), express the energy released in joules.
(c)[2]
Explain how neutrons released in fission can sustain a chain reaction in uranium-235.