A potentiometer is an ideal device of measuring potential difference because

Options

A. It has a sensitive galvanometer
B. It has wire of higher resistance
C. It measure p.d like in closed circuit
D. It measure p.d like in open circuit

Answer

To solve the question regarding why a potentiometer is considered an ideal device for measuring potential difference, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Potentiometer**:
- A potentiometer is a device used to measure the electromotive force (EMF) of a cell or to compare the EMF of two cells. It operates on the principle of balancing potential differences.

**Hint**: Recall that a potentiometer is used for measuring EMF and comparing voltages.

2. **Circuit Configuration**:
- The potentiometer consists of a primary circuit with a known voltage source, a rheostat, and a long resistance wire. The secondary circuit includes a galvanometer and an unknown cell.

**Hint**: Visualize the circuit layout with the known voltage source and the resistance wire.

3. **Balancing Condition**:
- When measuring the potential difference, the jockey is moved along the resistance wire until the galvanometer shows zero deflection. This indicates that the potential difference across the wire is equal to the EMF of the unknown cell.

**Hint**: Remember that zero deflection in the galvanometer indicates a balanced condition.

4. **Current Flow**:
- At the balancing length, there is no current flowing through the galvanometer and the secondary circuit. This is crucial because it means that the measurement is not affected by any current draw.

**Hint**: Think about how no current flow means no disturbance in the circuit.

5. **Open Circuit Condition**:
- Since the potentiometer measures the potential difference without any current flowing in the secondary circuit, it behaves like an open circuit. This is what makes it ideal for measuring potential differences without loading the circuit.

**Hint**: Consider how measuring in an open circuit allows for accurate potential difference readings.

6. **Conclusion**:
- Therefore, the reason a potentiometer is an ideal device for measuring potential difference is that it measures potential difference like in an open circuit, allowing for accurate measurements without any current interference.

**Hint**: Summarize that the open circuit condition is key to the potentiometer's accuracy.

### Final Answer:
A potentiometer is an ideal device for measuring potential difference because it measures potential difference like in an open circuit.