Medium level questions

## Electromagnetic Induction

- Want to practice more questions? Here are the Medium level questions
1
Calculate Magnetic Flux
Find the flux of the vector  through the spherical surface of radius , whose centre lies on the surface of the magnetic.
A
B
C
D
2
Calculate the induced emf in a closed loop.
A triangular wire frame (each side of ) is placed in a region of time variant magnetic field having . The magnetic field is perpendicular to the plane of the triangle. The base of the triangle AB has a resistance while the other two sides have resistance each. The magnitude of potential difference between the points A and B will be :
A
B
C
D
A flat coil, C, of n turns, area A and resisitance R is placed in a uniform magnetic field of magnitude B. The plane of the coil is initially perpendicular to B. If the coil is rotated by an angle about the axis XY, charge of amount Q flows through it.
This question has multiple correct options
A
If .
B
If .
C
If .
D
If .

In Figure , two straight conducting rails form a right angle. A conducting bar in contact with the rails starts at the vertex at time t = 0 and moves with a constant velocity of 5.20 m/s along them. A magnetic field with B = 0.350 T is directed out of the page. Calculate (a) the  flux through the triangle formed by the rails and bar at t = 3.00 s and
(b) the emf around the triangle at that time.

(c) If the emf is , where a and n are

constants, what is the value of n?

3
Calculate induced emf in a coil caused by varying flux due to magnetic field.
A solenoid with turns per metre and a radius of , carries a time varying current ) A. The electric field at a distance from the axis of the solenoid at will be in V m to the nearest integer )
A
B
C
D
4
Solve problem on moving conductor with a constant velocity in a circuit with capacitor.
Two metal bars are fixed vertically and are connected on the top by a capacitor C. A sliding conductor AB of length L slides with its ends in contact with the bars. The arrangement is placed in a uniform horizontal magnetic field directed normal to the plane of the figure. The conductor is released from rest. The displacement (x) in meter of the conductor at time is:
(Given )
A
B
C
D
Find the speed of the connector as a function of time if the force is applied at
5
Basic numerical on Mutual Inductance.
AB is an infinitely long wire placed in the plane of rectangular coil of dimensions as shown in the figure. Calculate the mutual inductance of wire AB and PQRS
A
B
C
D
None of these
6
Calculate mutual inductance of two inductors of different shapes.
A circular loop of radius lies parallel to a much bigger circular loop of radius . The centre of the small loop is on the axis of the bigger loop. The distance between their centres is . If a current of flows through the smaller loop, then the flux linked with bigger loop is
A
B
C
D

7
Find resultant magnetic induction at a particular point.
Two coplanar circular coils of equal radius carrying currents in opposite directions are at a large distacne 'd'. The distance from the first coil where the resultant magnetic induction is zero is
A
B
C
D
8
Find the current in the inductive circuit having both resistor and inductor.
An inductive circuit contains a resistance of 10 ohms and an inductance of 2 Henry. If an alternating voltage of 120 V and frequency 60 Hz is applied to this circuit, the current in the circuit would be nearly
A
B
C
D
9
Calculate the equivalent inductance of an inductive circuit.
Calculate the equivalent inductance of the following inductive circuit.
A
B
C
D
10
Solve problems on LR circuits involving multiple resistors and inductors.
In figure, switch S is closed for a long time. At t=0, if it is opened then,
A
total heat produced in resistor R after opening the switch is
B
total heat produced in resistor after opening the switch is
C
heat produced in resistor after opening the switch is
D
no heat will be produced in
11
Basic problem on dc and ac motors.
An electric motor operating on a dc supply draws a current of If the efficiency of the motor is , the resistance of its winding is
A
B
C
D