Question

When the North pole of a bar magnet is pushed towards the coil, the pointer in the galvanometer deflects. Fig. (i) show that it is the relative motion between the magnet and coil that is responsible for generation of electric current in the coil. In Fig. (ii), the bar magnet is replaced by a second coil $C_2$ connected to a battery. The steady current in the coil $C_2$ produces a steady magnet field.
As coil $C_2$ is moved toward the coil $C_1$, the galvanometer shows a deflection. Again, it is the relative motion between the coils that induces the electric current.

Consider the motion of a magnet towards or away from coil $C_1$ in Fig. (i) and moving a current carrying coil $C_2$ towards or away from coil $C_1$ in Fig. (ii). Magnetic flux associated with coil $C_1$

• A. changes in both (i) and (ii) situations
• B. changes in situation (i) but do not change in situation (ii)
• C. does not change in situation (i) but changes in situation (ii)
• D. does not change in both situations (i) and (ii)

Answer 1

Answer: (A)

The motion of a magnet towards or away from coil $C_1$ in Fig. (i) and moving a current-carrying coil $C_2$ towards or away from coil $C_1$ in Fig. (ii), change the magnetic flux associated with coil $C_1$. The change in magnetic flux induces emf in coil $C_1$. It is this induced emf which causes electric current to flow in coil $C_1$ and through the galvanometer.