In a metre bridge experiment (as shown in figure), the positions of the cell E, and gal vanometer G, are interchanged. We shall observe in the galvanometer: ____.

In a metre‑bridge (Wheatstone bridge) the galvanometer G is connected between the two arms of the bridge. When the bridge is balanced, the potential difference across the galvanometer is zero, so no current flows and the needle stays at the centre (no deflection).

In the original arrangement the cell E supplies the emf to one side of the bridge and the galvanometer G is placed on the opposite side. If we interchange the positions of the cell and the galvanometer, the emf now appears across the points where the galvanometer was originally connected.

Because the polarity of the emf with respect to the jockey (the movable contact) is reversed, the galvanometer will now experience a current that depends on which side of the balance point the jockey is placed:

• When the jockey is to the left of the balance point, the emf drives a current that pushes the galvanometer needle to the right – a right‑sided deflection.
• When the jockey is to the right of the balance point, the direction of the current reverses, causing a left‑sided deflection.
• Exactly at the balance point the potentials of the two arms become equal again, so the net voltage across the galvanometer is zero and the needle shows no deflection.

Thus, after interchanging the cell E and the galvanometer G we observe both right‑sided and left‑sided deflection depending on the jockey’s position, and at the exact balance position the galvanometer shows no deflection.