In the circuit shown below, the cell has an e.m.f. of 10 V and internal resistance of 1 ohm. The other resistances are shown in the figure. The potential difference $V_A-V_B$ is :

1. 6 V

2. 4 V

3. 2 V

4. –2 V

In the circuit, the potential difference across PQ will be nearest to 

1. 9.6 V

2. 6.6 V

3. 4.8 V

4. 3.2 V

The e.m.f. of a cell is E volts and internal resistance is r ohm. The resistance in external circuit is also r ohm. The p.d. across the cell will be 

1. E/2

2. 2E

3. 4E

4. E/4

The terminal potential difference of a cell when short-circuited is (E = E.M.F. of the cell)

1. E

2. E/2

3. Zero

4. E/3