Question

Explain why the p.d across the terminals of a cell is more in an open circuit and reduced in a closed circuit.

Answer 1

The potential difference is the energy difference between the charge carriers at two points in the circuit. Open circuit voltage is the potential difference between two connections when the device is disconnected from the circuit. No external load is connected. No external current flows between the terminals. A circuit is a "closed circuit" if it contains a full path between the positive and negative terminals of its power supply.

Complete answer:
When the battery is in a closed circuit, current flows through the circuit. The potential at the internal resistance of the battery drops. Therefore, the potential difference between the connections in a closed circuit is less than the potential difference between the open connections, and its magnitude is equal to the potential drop across the internal resistance of the battery.Thus, we explained the Potential difference across the terminals of a cell is more in an open circuit and reduced in a closed circuit.

Note: An ideal battery or battery has no internal resistance, i.e. r = 0. When the battery and some external components are connected in the circuit, the material in the battery has no voltage drop. If the battery is disconnected or open, no current will flow through it. The electromotive force is therefore the potential difference observed during the measurement. If the battery has the internal resistances r and is connected via a circuit, a current I flows in the circuit. There is therefore a voltage drop across this internal resistance.