# Chapter 27 - Worked Solutions

### to selected Scientific Processes and Complex Reasoning questions from the OUP text Senior Physics - Knowledge, Processes and Reasoning by Walding, Rapkins and Rossiter

Question 17
(a) Mass of components = mp + me + mn x 2
= 1.007276 + 0.000549 +1.008665 x 2 = 3.025155 u
D m = 3.016049 - 3.025155 = 9.106 x 10-3
E = 931 x 9.106 x 10-3 = 8.4776 MeV

(b) Mass of components = mp x 2 + me x 2 + mn x 1
= 1.007276 x 2 + 0.000549 x 2 + 1.008665 = 3.024315
D m = 3.024315 - 3.016030 = 8.285 x 10-3 u = 7.713 MeV

Question 23
(i)
(a) 16 x 1.007276 + 19 x 1.008665 + 16 x 0.000549 = 35.289835 u
D m = 35.289835 - 34.969033 = 0.320802
(b) E = 298.66 MeV = 298.66/35 MeV/nucleon = 8.5 MeV/nucleon

(ii)
(a) 92 x 1.007276 = 92.66932
+ 143 x 1.008665 = 144.239095
+ 92 x 0.000549 = 0.050508
Total = 236.958995 u
D m = 1.915055 u
(b) E = 1782.9 MeV = 7.58 MeV/nucleon

(iii)
(a) 48 x 1.007276 + 65 x 1.008665 + 48 x 0.000549 = 113.93883 u
D m = 1.034425 u
(b) E = 963 MeV = 8.5 MeV/nucleon

(iv)
(a) 3 x 1.007276 + 4 x 1.008665 + 3 x 0.000549 = 7.058135 u
D m = 0.042131 u
(b) E = 39.22 MeV = 5.6 MeV/nucleon

Question 26
E = 1200/(2.4 x 10-2) = 50000 vm-1
m = qE/g = 3 x 1.6 x 10-19 x 50000/9.8 = 2.44 x 10-15 kg

Question 27
q = mg/E = 3.52 x 10-14 x 9.8/(9.8 x 10-14) = 3.52 x 10-18 C
number of electrons = 3.52 x 10-18 C/(1.6 x 10-19C) = 22

Question 28
D

Question 29
F