the reading on the high resistance voltmeter when connected across it is 2 2V When the terminals of the - Physics -

Question

the reading on the high resistance voltmeter when connected
across it is 2 2V When the terminals of the cell are also connected
to a resistance of 5 ohms, the voltmeter reading drops to 1 8V Find
the internal resistance of the cell

Pratyay Ghosh · Accepted Answer

The emf of the cell is 2 2 V
Then when the cell is connected to a 5 ohm resistance the current
will be,=2 2(r+5)
r is the internal resistance of the cell
On the other hand, the current in the circuit is also =1 85
So,
2 2r+5=1 85⇒r=1 11 Ω

the reading on the high resistance voltmeter when connected across it is 2.2V. When the terminals of the cell are also connected to a resistance of 5 ohms, the voltmeter reading drops to 1.8V. Find the internal resistance of the cell.