Or
Option 2
Or
Option 3
Or
Option 4
8.1

(Electrical) energy/work Unit charge Tip: the emf of the battery is the maximum energy/work provided by a battery per unit of charge passing through it. 
2 marks (2 x 1 mark)

8.2

How to approach this question: Option 1

4 marks (4 x 1 mark)

8.3.1

How to approach this question:
When the switch is open: ^{(1)} ^{(2)}
^{(4)} ^{(5)} Or ^{(4)} ^{(5)} When the switch is closed:
^{(1)} ^{(3)}
^{(4)} ^{(5)} Or ^{(4)} ^{(6)}
^{(7)} ^{(8)} Or ^{(7)} ^{(8)} 
8 marks (8 x 1 mark) Marking criteria: Calculation of current when the switch is open and when closed:
Substitution into formula ε = I(R + r) or ε = V_{ext} + Ir:
Calculating r:

8.3.2

Option 1 Tip: the marks are awarded for the correct substitution of the value of the internal resistance into any formula used in question 8.3.1 There are more ways to answer this question. To view other options, click here. 
2 marks (2 x 1 mark)

Or
Option 2
Or
Option 3
Or
Option 4