A cell of internal resistance r is connected to an external resistor R. The conductor for maximum power transfer is?

Answer Details

When a cell is connected to an external resistor, the power delivered to the resistor is maximum when the resistance of the external resistor matches the internal resistance of the cell. This is known as the maximum power transfer theorem.
In this case, the internal resistance of the cell is given as "r" and the external resistance is "R". Therefore, the conductor for maximum power transfer would be when R = r, i.e., when the external resistor has the same value as the internal resistance of the cell.
So the answer is: R = r.