Eight cells marked 1 to 8 each of emf 5 V and internal resistance 0.2 ohm are connected as shown in figure. What is the reading of the ideal voltmeter V?
The emfs of cells connected in reverse polarity cancel each other. Hence cells marked 2, 3 and 4 together cancel the effect of cells marked 5, 6 and 7 and the circuit reduces to that shown in figure. Now cells 1 and 8 are in reverse polarity. Hence the voltmeter reading = 5 – 5 = 0 V