Question

The following diagram in figure shows a fixed coil of several turns connected to a centre zero galvanometer G and a magnet NS which can move in the direction shown in the diagram. How would the observation alter if a more powerful magnet is used?

Answer 1

When a magnet is moved closer to the current carrying coil it will generate electricity as the coil moves through the magnetic field. As the magnet is moved, there will be an induced electro-motive force (EMF) which can cause a current in the coil. Once the magnet stops moving, the current will go to zero.
Hence, when a galvanometer is connected to the circuit, there will be deflection due to the flow of electricity. As the magnet is moved toward the coil of wire, the needle of the galvanometer moves one direction. As the magnet is moved away from the coil of wire, the needle of the galvanometer moves the opposite direction. If the magnet is moved faster, the magnitude of the deflection increases rapidly.
When a stronger magnet is used instead of the one with less magnetic power, the deflection in the galvanometer increases because the strength of the magnetic field increases with a more powerful magnet, which in turn increases the amount of current. The strength of magnetic field is directly proportional to amount of current through the coil.