The diagram in the figure shows a cell of e.m.f. ε=2 volt and internal resistance r = 1 ohm connected to an external resistance R = 4 ohm. The ammeter A measures the current in the circuit and the voltmeter V measures the terminal voltage across the cell. What will be the readings of the ammeter and voltmeter when (i) the key K is open, and (ii) the key K is closed?
(i) Ammeter reading = 0 because its an open circuit.
Voltmeter reading = e.m.f. of the cell = 2 V (As no current is being drawn from the cell)
(ii) Ammeter reading