NCERT Solutions for Chapter: Electromagnetic Induction, Exercise 2: VSA

Consider a magnet surrounded by a wire with an on/off switch $\mathrm{S}$ (Figure). If the switch is thrown from the off position (open circuit) to the on position (closed circuit), will a current flow in the circuit? Explain.

A wire in the form of a tightly wound solenoid is connected to a DC source, and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil, will the current increase or decrease? Explain.

A solenoid is connected to a battery so that a steady current flows through. If an iron core is inserted into the solenoid, will the current increase or decrease? Explain.

Consider a metal ring kept on top of a fixed solenoid (say on a cardboard) (figure). The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched on, the metal ring jumps up. Explain

Consider a metal ring kept (supported by a cardboard) on top of a fixed solenoid carrying a current $\mathrm{I}$ (see Figure). The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off. What will happen to the ring?

Consider a metallic pipe with an inner radius of $1 \mathrm{cm}$. If a cylindrical bar magnet of radius $0.8 \mathrm{cm}$ is dropped through the pipe, it takes more time to come down than it takes for a similar un-magnetized cylindrical iron bar dropped through the metallic pipe. Explain.