Electromagnetic Induction and Alternating Currents

Lenz's law is a consequence of the law of conservation of:

A straight rod 0.5 m long moves at 4 m/s perpendicular to its length and to a uniform magnetic field of 0.2 T. The emf induced between its ends is:

The north pole of a bar magnet is moved towards one face of a closed coil. The face of the coil nearer the magnet behaves as:

A small strong magnet is dropped into a long vertical copper tube. Compared with free fall, it:

A metal rod 1 m long rotates at 20 rad/s about an axis through one end, perpendicular to the rod and parallel to a uniform field of 0.5 T. The emf between the ends of the rod is:

A conducting rod 0.5 m long slides at a constant 4 m/s on two parallel rails joined by a 2 Ω resistor, in a uniform field of 0.5 T perpendicular to the plane of the rails. Neglecting other resistances and friction, the external force needed to keep it moving is:

A conducting rod 0.5 m long slides at a constant 4 m/s on two parallel rails joined by a 2 Ω resistor, in a uniform field of 0.5 T perpendicular to the plane of the rails. The power dissipated in the resistor is:

The iron core of a transformer is made of thin insulated laminations in order to:

A metal disc of radius 0.1 m rotates at 50 revolutions per second about its axis, which is parallel to a uniform magnetic field of 0.5 T. The emf between the centre and the rim of the disc is about:

The direction of the current induced in a conductor moving in a magnetic field is given by:

A rectangular conducting loop is being pulled out of a region of uniform magnetic field directed into the page. The current induced in the loop (seen from the front) is:

A straight rod 2 m long moves with a velocity of 3 m/s in a uniform field of 0.1 T. The velocity is perpendicular to the field and makes an angle of 30° with the length of the rod (the rod also lies in the plane perpendicular to B). The emf between its ends is:

Two coaxial circular loops face each other. If the current in one loop is increased, the current induced in the other loop:

A rod 10 cm long moves at 2 m/s perpendicular to its length and to a uniform magnetic field of 0.3 T. Find the emf between its ends in millivolt.

A rod 0.5 m long rotates at 40 rad/s about one end in a plane perpendicular to a uniform field of 0.2 T. Find the emf between its ends in volt.

A rod sliding on conducting rails develops a motional emf of 2 V. The circuit has a total resistance of 4 Ω. Find the induced current in milliampere.