Solution:
The expression for the equivalent resistance of the combination of resistors in a series combination isGiven the resistors are connected in series with a battery, key, and the ammeter connected. The current I flows through the circuit. The current remains the unchanged in series combination.
Let the voltage (potential difference) across each resistance be .
Using Ohm's law we have
Total potential difference across the circuit
Therefore
Here in a series combination of resistors, the equivalent resistance is equal to the sum of the individual resistances.