In a metre bridge experiment (see figure), the positions of the cell, $E$, and galvanometer, $G$, are interchanged. We shall observe in the galvanometer:

![](https://res.cloudinary.com/ddr1kuyb3/image/upload/v1786186801/questions/euzeysis93etpstes5fb.png)

Question

In a metre bridge experiment (see figure), the positions of the cell, $E$, and galvanometer, $G$, are interchanged. We shall observe in the galvanometer:

![](https://res.cloudinary.com/ddr1kuyb3/image/upload/v1786186801/questions/euzeysis93etpstes5fb.png)

Accepted Answer

D. 1. **Recall the balance condition of a metre bridge.** A metre bridge is essentially a Wheatstone bridge, and its balance point depends only on the ratio of resistances in the four arms — not on which diagonal holds the cell and which holds the galvanometer.

2. **Apply this to swapping E and G.** Since the resistance arms are unchanged, interchanging the cell and the galvanometer does **not** shift the position of the null (balance) point.

3. **Consider what happens away from the balance point.** When the jockey is not at the balance point, swapping E and G changes the direction in which current is driven through the galvanometer branch, so the deflection may show up on either the left side or the right side of the balance point depending on the jockey's position.

4. **Consider what happens exactly at the balance point.** At the true balance point, no current flows through the galvanometer branch at all, so there is **no deflection** there, regardless of the interchange.

5. Putting this together: deflection can appear on both sides of the null point, but vanishes exactly at the balance point.

Hence, the answer is **Option D**.

In a metre bridge experiment (see figure), the positions of the cell, EEE, and galvanometer, GGG, are interchanged. We shall observe in the galvanometer:

In a metre bridge experiment (see figure), the positions of the cell, $E$ , and galvanometer, $G$ , are interchanged. We shall observe in the galvanometer: