Answers to Current of Electricity Tutorial

Please take note of the following typo in your CoE tutorial, self-attempt question 1b):

Each copper atom has 29 electrons NOT 64 electrons. (It's atomic number is 29, but mass number is 64)

S1 a) 8.98 x 10^-4 kg
b) No. of Cu atoms = 8.36 x 10^21
No. of electrons = 2.4 x 10^23
c) number of electrons moving per second = 6.25 x 10
fraction = 2.58 x 10^-5

S2) 20 C

S3 a) 600 kJ
b) 2500 C
c) 0.25 A

S4 case1: 6897 Ohm
case 2: 113 Ohm

S5 a) I = 2.0 A, R = 6.0 Ohm
b) pd = 6 V, Power dissipated = 12 W

S6 a) pd = 0.9 V, I = 4.1 x 10^-4 A
b) No change
c) R = 300 Ohm

7a) R = 0.175 Ohm
b) 3.51 x 10^-5 Ohm metre

8a) 86.4 MJ, 24 kWh
b) $3.96

9) R = 384 Ohm, l = 0.04 m

10) E = 21.1 V, r = 0.56 Ohm

11) She never give me solutions =(

12) increases by 4 times

13) We go through in class

14) 6.25 x 10^17 ions per second

15 (a)(b): E = 0.3 V, r = 1000 Ohm
(c) 0.225%

16 (b) 0.0114 Ohm
(c)(i) 1050 A
(d)(i) 1.8 x 10^5 C
(ii) 28.6 min

17(a) Total bill: $415.97