Case: Read the following passage and answer accordingly.
The current through a single resistor R across which there is a potential difference V is given by Ohm’s law \( I=V/R \). Resistors are sometimes joined together and there are simple rules for the calculation of equivalent resistance of such a combination. Two resistors are said to be in series if only one of their endpoints is joined. Two or more resistors are said to be in parallel if one end of all the resistors is joined together and similarly the other ends joined together.
In a series combination of resistors,
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → the current through each resistor is the same
In a series combination, the resistors are joined end to end and offer a single path to the charges.
Option (1) the voltage across each resistor is the same — Incorrect. The voltage across each resistor is \( IR \), so it differs for different resistances. Equal voltage is the property of a parallel combination.
Option (2) neither the voltage nor the current is the same — Incorrect. The current through resistors in series is the same, since the charges have only one path.
Option (3) the current through each resistor is the same — Correct. Charge does not pile up anywhere along the path. So the same current flows through every resistor. The potential difference across each one is \( V=IR \), and these voltages add up to the applied voltage.
Option (4) both the current and the voltage are the same — Incorrect. The voltage \( IR \) across each resistor differs for different resistances, so only the current is common.