The p.d. between the terminal of a cell in an open circuit was . When it was measured across a resistor of it was found to be . The internal resistance of the cell is
Step 1: Give data:
Open circuit emf of the cell is
When measured across the resistor the Voltage becomes
Step 2: Calculating the internal resistance,
We have a relation
Also, we know
Where = internal resistance putting in ()
Now we substitute the given values
Thus, the correct answer is option A,.