1.1. The electromotive force, E  is defined by the equation 

E = I (R + r) 

State the definition of the following variables and an appropriate unit for each. 

(i) I

[1]

(ii) R

[1]

(iii) r

[1]

1.2. A circuit connecting a cell with internal resistance to a resistor is shown in Fig. 1.1.  

Fig. 1.1

Place in each of the grey boxes one of the following variables: 

1.3. A current of 0.6 mA flows through the circuit in Fig. 1.1 and the resistor has a resistance of 2.5 kΩ. 

Calculate the terminal potential difference of the circuit.

1.4. The internal resistance of the cell is 1.3 kΩ. 

Calculate the emf of the cell using the equation E.m.f. E = I (R + r).