Consider a metal rign kept on top of fixed solenoid carrying a current as shown in the figure . The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched off, what will happen to the ring?

Consider a metal ring kept on the top of a fixed solenoid (say on a cardboard) (Fig. EP 6.14). 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.

A current of 10 A flow around a closed path in a circuit which is in the horizontal plane as shown in the figure. The circuit consists of eight alternative arcs of radii r_(1)=0.08m and r_(2)=0.12m . Each subtends the same angle at the centre. An infinitely long straight wire carrying a current of 10 A is passing throgh the entre of the above circuit vertically with the direction of the current being into the plane of the circuit. What is the force acting on the wire at the centre due to the current in the circuit? What is the force acting on the arc AC and the straight segment CD due to the current at the centre?

A small resistor is usually put in a parallel t the current carrying coil of an electromagnet as shown in the figure. What purpose does it serve?

An electron is moving with velocity vecv along the axis of a long straight solenoid carrying current 'I'. What will be the force acting on the electron due to the magnetic field of the solenoid?

A long solenoid carrying a current produces a magnetic field B along its axis. If the number of turns per cm is doubled and the current in the solenoid is halved, then the new value of the magnetic field along its axis will be

A solenoid 60 cm long and of radius 4.0 cm has 3 layers of windings of 300 turns each. A 2.0 cm long wire of mass 2.5 g lies inside the solenoid (near its centre) normal to its axis, both the wire and the axis of the solenoid are in the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to an external battery which supplies a current of 6.0 A in the wire. What value of current (with appropriate sense of circulation) in the windings of the solenoid can support the weight of the wire? g = 9.8 m s^-2 .

A wire loop is formed by joining two semicircular wires of radii r_1 and r_2 as shown in the figure . The loop carries a current I, find the magnetic field at the centre O.

A rubber band is covered with a conducting and current passed through it in the direction as shown in the figure. What happens, if the current is reversed in the rubber band