A solenoid with a length of 20.0 cm has a total of 1260 turns of wire. If its cross-sectional area is 12.0 cm² , the inductance of solenoid is

When power is supplied to an electric motor, the motor armature rotates in a magnetic field and induced e.m.f. is generated. Which statement about the motor is not true ?

A small coil with 100 turns of cross-sectional area 1.26 x 10^-3 m² is placed coaxially at the centre of a solenoid with 3000 turns and length 2.44 m. What is the mutual inductance between the solenoid and the coil ?

A conducting rod being pulled from rest to move with constant acceleration in a uniform magnetic field on two horizontal tracks of negligible resistance is shown in the diagram below.

The tracks are connected to a resistor R at both of its ends. Which graph shows the variation of the induced current I with time t for the conducting rod ?

A circular conducting loop is connected to a battery and a switch S as shown in the diagram.

Immediately after S is closed, the current through the loop changes at a rate of 15.0 As^-1,and the e.m.f. induced in the loop has a magnitude of 5.0 V. What is the self - inductance of the loop ?

A straight conductor of length 1.20 m is moving in magnetic field of 2.50 T with constant velocity. Assume that  $R=6.0\Omega$   and that the uniform magnetic field is directed into the page. At what speed should the conductor be moving to produce a current of 0.500 A in the resistor ?

Back e.m.f. is induced in a spinning electric motor. Which statement about the back e.m.f is NOT true ?

A metal conductor of length 20.0 cm which is being moved with a constant velocity of $5.0ms^{-1}$     by a constant force F in a uniform magnetic field of 4.0 T is shown in the diagram below.
The ends of the conducting track which has negligible resistance is connected to a resistor  $5.0\Omega$  . What is the magnitude of force F ?

The figure below shows the side view of a circular coil of N turns and area A in a magnetic field B.
If the normal to the plane of the coil makes an angle  $\alpha$  with the magnetic field, the magnetic flux through the coil is

The figure below shows a uniform magnetic field,B, directed to the left and a wire carrying a current, I, out of page.

The magnetic force acting on the wire is directed

An ideal solenoid 50 cm long has 4000 loops wound on it. Compute the magnetic field, B, in its interior when a current of 0.25 A flows through it.

The figure below shows four parallel wires passing vertically through the four vertices of a square PQRS. These wires carry current of equal magnitude in the direction as shown.

The direction of the resultant magnetic field at the centre O of the square is along

The figure below shows a 40 cm straight rod carrying a current of 20 A in a horizontal magnetic field B which makes an angle of 30^o with the rod.

If the weight of the rod is 8.0 N and the magnetic force is just enough to balance the weight of the rod, what is the magnitude field strength of B ?

The figure below shows a beam of protons moving in a straight path through a region that has a magnetic field and an electric field.

The electric field is produced two plates CD and MN which are 5.0 cm apart with potential difference of 2000 V. If the magnetic field 2.0 x 10^-3 T, find the speed of the protons.