Author: The Momma
Last saved by: JONES

A2 Fusion Questions - Solutions

1.	A	2.	B
3.	B	4.	B
5.	(a)	
	graph to show:
steep rise, maximum and gradual fall,
with maximum between 6 MeV and 10 MeV (1)
suitable values of A (up to 200 - 250) (1)
maximum shown at A » 60, with fall < 20% of rise (1)	3
(b)	(i)	fission when nucleus splits into two nuclei
and
fusion when two nuclei join to form one nucleus (1)
(ii)	energy released when B.E./nucleon increases
or when B.E. increases
or when greater stability results
[or by movement towards peak of graph] (1)
	how fission achieves this (1)
how fusion achieves this (1)
[ if not explained, award (1) (one only) if fusion and fission
	arrows shown correctly on graph]	max 3
	The Quality of Written Communication marks are awarded for the quality of answers to this question.
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6.	(a)	mass difference increases
or B.E. (per nucleon) or stability is greater for nucleus after fusion  (1)
(greater) mass difference
or increase in B.E. (per nucleon) implies energy released  (1)
both nuclei charged positively or have like charges  (1)
electrostatic repulsion  (1)	max 3
	QWC 2

(b)	(i)	Dm (= 2 × (2.01355) – (3.01493 + 1.00867))
    = 3.5 × 10^–3 u  (1)    (5.81 × 10^–30 kg)
(ii)	DE = 3.5 × 10^–3 × 931.3 (MeV)  (1)            (= 3.26 MeV)
= 3.26 × 10^6 × 1.6 × 10^–19 = 5.22 × 10^–13 (J)  (1)	3
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