Assertion : Potentiometer is used only to compare potential differences.
Reason: The potentiometer draws current from the voltage source being measured .

Options

A. If both assertion and reason are true and reason is the correct explantion of assertion.
B. If both assertion and reason are true and reason is not the correct explantion of assertion.
C. If assertion is false but reason is true.
D. If assertion is true but reason is false.

Explanation

To analyze the assertion and reason provided in the question, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Potentiometer is used only to compare potential differences."
- This is true because a potentiometer is designed to measure the potential difference (voltage) between two points without drawing any significant current from the source being measured. It compares the EMF of different cells by balancing the potential difference across a known length of wire.

2. **Understanding the Reason**:
- The reason states that "The potentiometer draws current from the voltage source being measured."
- This statement is false. A potentiometer operates on the principle of null deflection, which means it does not draw current from the source being measured when it is balanced. Instead, it measures the potential difference by comparing it to a known reference voltage without affecting the circuit.

3. **Conclusion**:
- Since the assertion is true and the reason is false, we can conclude that the assertion is correct in its claim about the purpose of a potentiometer, while the reason provided is incorrect regarding the operation of the potentiometer.

### Final Answer:
- The assertion is true: A potentiometer is indeed used to compare potential differences.
- The reason is false: A potentiometer does not draw current from the voltage source being measured.