Question

You are provided with 48 cells, each of emf 2 volts
and internal resistance 4 ohms. What maximum
current can flow in the circuit having an external
resistance of 12 12 ?
(1) 1 A
(2) 1.2 A
(3) 0.96 A
(4) 1.08 A​

Answer 1

The current flowing in the circuit is 1 A.

Explanation:

Given data:

E = 2 V

r = 2 ohm

R = 12 ohm

Let there are m cells in one row and there are m such cells.

m x n = 48

Now equivalent resistance of each row = r1 = mr

Total equivalent resistance of the circuit = req = mr / n

m x 4 / n = 12 => m = 3n

From equation 1

3n x n = 48    => n = 4 , m = 12

Net equivalent emf of the circuit

Eeq = Σ Ei / ri x req

Where i represents row number.

I = Eeq / rEq + R = 24 / 12 + 12 = 1 A

Hence the current flowing in the circuit is 1 A.