(a) A galvanometer is used because it can detect very small currents. When the magnet moves towards the coil, the magnetic flux through the coil changes, inducing an EMF and a momentary current — causing the needle to deflect. The deflection is momentary because current is induced only while flux is changing.
(b) No deflection would be observed. When coil and magnet move with the same speed in the same direction, there is no relative motion between them, so magnetic flux does not change and no EMF is induced.
(c) Conclusion: A changing magnetic flux (relative motion between magnet and coil) induces an electric current — this is electromagnetic induction.
Yes, deflection increases — more turns increase the flux linkage and a stronger magnet produces greater flux change, both resulting in higher induced EMF and larger deflection.
Source: Chapter – Magnetic Effects of Electric Current (Electromagnetic Induction activity)
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