In a wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will

Options

A. change in previous direction
B. not change
C. change in opposite direction
D. none of these.

Explanation

To solve the question regarding the deflection in the galvanometer when the battery and galvanometer are interchanged in a Wheatstone bridge, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Wheatstone Bridge Configuration**:
A Wheatstone bridge consists of four resistances (let's denote them as P, Q, R, and S) arranged in a diamond shape. A galvanometer is connected between the junction of P and Q and the junction of R and S. A battery is connected across the bridge.

2. **Initial Condition**:
In the balanced condition of the Wheatstone bridge, the ratio of the resistances is given by:
\[ \frac{P}{Q} = \frac{R}{S} \]
This can also be expressed as:
\[ PS = QR \]
In this state, the galvanometer shows no deflection.

3. **Interchanging Battery and Galvanometer**:
When we interchange the positions of the battery and the galvanometer, the galvanometer is now connected where the battery was, and the battery is connected where the galvanometer was.

4. **New Configuration**:
The new configuration will still have the same resistances P, Q, R, and S. The galvanometer is now in series with one of the resistances, and the battery is in the position where the galvanometer was.

5. **Analyzing the New Condition**:
The new circuit can be analyzed similarly. The balancing condition remains the same because the ratios of the resistances have not changed. Therefore, we still have:
\[ \frac{R}{P} = \frac{S}{Q} \]
This means that the condition for balance is still satisfied.

6. **Conclusion on Deflection**:
Since the balancing condition remains unchanged, the deflection in the galvanometer will also remain unchanged. Thus, the deflection in the galvanometer will be zero, just as it was in the initial condition.

### Final Answer:
The deflection in the galvanometer will **not change** when the battery and galvanometer are interchanged.

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