JEE Questions for Physics Electromagnetic Induction Quiz 2 - MCQExams.com

A 50 turns circular coil has a radius of 3 cm, it is kept in a magnetic field acting normal to the area of the coil. The magnetic field B increased from 0.10 T to 0.35 T in 2 ms. The average induced emf in the coil is
  • 1.77 V
  • 17.7 V
  • 177 V
  • 0.177 V
A current passing through a coil of self inductance of 2 mH changes at the rate of 20 mAs-1 . The emf induced in the coil is
  • 10 µV
  • 40 µV
  • 10 mV
  • 40 mV
An inductor having coefficient of self induction 40 mH. What is the energy stored in it, when a current of 2 A is passed through it ?
  • 40 mJ
  • 80 mJ
  • 20 mJ
  • 100 mJ
Magnetic flux linked with a coil is ϕ = 5t2 + 2 t + 3, where t is in sec and ϕ is in weber. At time t =1 s, the value of induced emf in volt.
  • 14
  • 1.2
  • 12
  • 6
Near a circular loop of conducting wire as shown in the figure, an electron moves along a straight line. The direction of the induced current if any in the loop is
Physics-Electromagnetic Induction-68615.png
  • variable
  • clockwise
  • anti-clockwise
  • zero
A metal disc of radius 100 cm is rotated at a constant angular speed of 60 rads -1 in a plane at right angles to an external field of magnetic induction 0.05 Wbm-2. The end' induced between the centre and a point on the rim will be
  • 3 V
  • 1.5 V
  • 6V
  • 9 V
A horizontal straight wire 10 m long extending from East to West is falling with a speed of 5.0 ms-1 at right angles to the horizontal component of the earth's magnetic field of strength 0.30 × 10-4 Wbm-2. The instantaneous value of the induced potential gradient in the wire, from West to East, is
  • + 1.5 × 10-3 Vm-1
  • - 1.5 × 10-3 Vm-1
  • + 1.5 × 10-4 Vm-1
  • - 1.5 × 10-4 Vm-1
An uniformly wound solenoid coil of self inductance 1.8 × 10-4 H and resistance 6 Ω is broken up into two identical coils. These identical coils are then connected in parallel across a 12 V battery of negligible resistance. The time constant for the current in the circuit is
  • 0.1 × 10-4 s
  • 0.2 × 10-4 s
  • 0.3 × 10-4 s
  • 0.4 × 10-4 s
Two similar circular loops carry equal currents in the same direction. On moving coils further apart, the electric current will
  • increase in both
  • decrease in both
  • remain unaltered
  • increases in one and decreases in the second

Physics-Electromagnetic Induction-68620.png
  • straight line through the origin
  • straight line with positive intercept
  • straight line with negative intercept
  • parabola through the origin
  • parabola not through the origin
Lenz's law of electromagnetic induction corresponds to the
  • law of conservation of charge
  • law of conservation of energy
  • law of conservation of momentum
  • law of conservation of angular momentum
A conducting rod of length l is moving in a transverse magnetic field of strength B with velocity v. The resistance of the rod is R. The current in the rod is

  • Physics-Electromagnetic Induction-68622.png
  • Blv
  • zero

  • Physics-Electromagnetic Induction-68623.png
Whenever a magnet is moved either towards or away from a conducting coil, an emf is induced, the magnitude of which is independent of
  • the strength of the magnetic field
  • the speed with which the magnet is moved
  • the number of rums of the coil
  • the resistance of the coil
According to Lenz's law of electromagnetic induction,
  • the induced emf is not in the direction opposing the change in magnetic flux
  • the relative motion between the coil and magnet produces change in magnetic flux
  • only the magnet should be moved towards coil
  • only the coil should be moved towards magnet
A square coil of side 25 cm having 1000 turns is rotated with an uniform speed in a magnetic field about an axis perpendicular to the direction of the field. At an instant t, the emf induced in the coil is e = 200 sin 100πt. The magnetic induction is
  • 0.50 T
  • 0.02 T
  • 10 -3 T
  • 0.1 T
  • 0.01 T
If a coil of 40 turns and area 4.0 cm2 is suddenly removed from a magnetic field, it is observed that a charge of 2.0 × 10-4 C flows into the coil. If the resistance of the coil is 80 Ω , the magnetic flux density in Wbm-2 is
  • 0.5
  • 1.0
  • 1.5
  • 2.0
Consider the statements.
I. If magnetic field, B = 0, then magnetic flux is also zero.
II. If magnetic flux, ϕ = 0, then magnetic field is also zero.
  • Statement I is true, Statement II may be true
  • Both Statement I and Statement II are true
  • Statement I may be true, Statement II is true
  • Statement I and Statement II both are false
The net magnetic flux through any closed surface, kept in a magnetic field is
  • zero
  • 2)
    Physics-Electromagnetic Induction-68628.png

  • Physics-Electromagnetic Induction-68629.png

  • Physics-Electromagnetic Induction-68630.png
A copper disc of radius 0.1 m is rotated about its centre with 20 rev s-1 in a uniform magnetic field of 0.1 T with its plane perpendicular to the field. The emf induced across the radius of the disc is

  • Physics-Electromagnetic Induction-68631.png
  • 2)
    Physics-Electromagnetic Induction-68632.png
  • 20 π mV
  • 10 π mV
  • 2 π mV
An infinitely long cylinder is kept parallel to an uniform magnetic field B directed along positive Z-axis. This direction of induced current as seen frotn the Z-axis will be
  • clockwise of the positive Z-axis
  • anti-clockwise of the positive Z-axis
  • zero
  • along the magnetic field

Physics-Electromagnetic Induction-68634.png
  • 0.08 C
  • 0.8 C
  • 0.008 C
  • 8 C
The magnitude of the earth's magnetic field at a place is B0 and the angle of dip is δ. A horizontal conductor of length l lying magnetic North South moves Eastwards with a velocity v, the emf induced across the conductor is
  • zero
  • B0 lv sin δ
  • B0 lv
  • B0 lv cos δ
  • B0 sin δ
Two coils have a mutual inductance 5 mH. The current changes in the first coil according to equation I = I0 sin ωt, where, I0 =10 A and ω =100 π rad /s. The maximum value of emf in the second coil is
  • 2π
  • 5π
  • π
  • 4π
A solenoid 30 cm long is made by winding 2000 loops of wire on an iron rod whose cross-section is 1.5 cm2. If the relative permeability of the iron is 6000. What is the self inductance of the solenoid ?
  • 1.5 H
  • 2.5 H
  • 3.5 H
  • 0.5 H
A coil of wire of radius r has 600 turns and a self inductance of 108 mH. The self inductance of a coil with same radius and 500 turns is
  • 80 mH
  • 75 mH
  • 108 mH
  • 90 mH
The energy stored in an inductor of self inductance L henry carrying a current of 1 A is
  • L2 I
  • -LI2

  • Physics-Electromagnetic Induction-68640.png

  • Physics-Electromagnetic Induction-68641.png
What is the self inductance of a solenoid of length 31.4 cm, area of cross section 10-3 m2 and total number of turns 103 ?
  • 4 mH
  • 4 H
  • 40 H
  • 0.4 H
Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area A = 10 cm2 and length = 20cm. If one of the solenoids has 300 turns and the other 400 turns, their mutual inductance is ( µ0 = 4π × 10-7 TMA-1)
  • 2.4π × 10-5 H
  • 4.8π × 10-4 H
  • 4.8π × 10-5 H
  • 2.4π × 10-4 H
Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon
  • the rates at which currents are changing in the two coils
  • relative position and orientation of the two coils
  • the materials of the wires of the coils
  • the currents in the two coils
A short solenoid of length 4 cm, radius 2 cm and 100 turns is placed inside and on the axis of a long solenoid of length 80 cm and 1500 turns. A current of 3 A flows through the short solenoid. The mutual inductance of two solenoids is
  • 2.96 × 10 -4 H
  • 5.3 × 10 -5 H
  • 3.52 × 10 -3 H
  • 8.3 × 10 -4 H
  • 2.96 × 10 -3 H
A solenoid 60 mm long has 50 turns on it and is wound on an iron rod of 7.5 mm radius. Find the flux through the solenoid when the current in it, is 3A. The relative permeability of iron is 600.
  • 1.66 Wb
  • 1.66 nWb
  • 1.66 mWb
  • 1.66 μWb
  • 1.66 pWb
A small square loop of wire of side l is placed inside a large square loop of side L (L >> l). If the loops are coplanar and their centres coincide, the mutual induction of the system is directly proportional to

  • Physics-Electromagnetic Induction-68646.png
  • 2)
    Physics-Electromagnetic Induction-68647.png

  • Physics-Electromagnetic Induction-68648.png

  • Physics-Electromagnetic Induction-68649.png
The induction coil works on the principle of
  • self induction
  • mutual induction
  • Ampere's rule
  • Flemidg's right hand rule
Coefficient of coupling between two coils of self inductances L1 and L2 is unity. It means
  • 50% flux of L1 is linked with L2
  • 100% flux of L1 is linked with L2

  • Physics-Electromagnetic Induction-68651.png
  • None of the above
A coil having area 2m2 is placed in a magnetic field which changes from 1 wb/m2 to 4 wb/m2 in an interval of 2 second. The emf induced in the coil of single turn is....
  • 4 v
  • 3 v
  • 1.5 v
  • 2 v
Two different loops are concentric & lie in the same plane. The current in outer loop is clockwise & increasing with time. The induced current in the inner loop then, is..........
  • direction depends on the ratio of loop radii
  • clockwise
  • zero
  • counter clockwise
A magnetic field 2 × 10–2 T acts at right angles to a coil of area 200 cm2 with 25 turns. The average emf induced in the coil is 0.1 v when it removes from the field in time t. The value of t is
  • 0.1 sec
  • 1 sec
  • 0.01 sec
  • 20 sec
The magnetic flux linked with a coil, in webers, is given by the equation ϕ = 4t2 – 3t + 7. Then the magnitude of induced emf at 2 sec will be ...
  • 15 v
  • 19 v
  • 17 v
  • 21 v
When a train travels with a speed 360 km h–1 along the track separated by 1 meter. The vertical component of earth's magnetic field is 0.1 × 10–4 T. What is the value of induced emf between the rails ?
  • 10–2 V
  • 10–4 V
  • 10–3 V
  • 1 V
An electron moves along the line AB,which lies in the same plane as a circular loop of conducting wires as shown in figure. What will be the direction of current induced if any, in the loop ?
Physics-Electromagnetic Induction-68653.png
  • No current will be induced
  • The current will be clockwise
  • The current will be anticlockwise
  • The current will change direction as the electron passes by
A circular loop of radius R carrying current I lies in X – Y plane with its center at origin. The total magnetic flux through x – y plane is.....
  • Directly proportional to I
  • Directly proportional to R
  • Directly proportional to R2
  • zero
Two similar circular loops carry equal currents in the same direction. On moving the coils further apart, the electric current will
  • Remain unchanged
  • Increasing in both
  • Increasing in one decreasing in other
  • Decreasing in both
When the number of turns in a coil is make four time without any change in length of the coil, its self inductance becomes......
  • unchanged
  • two times
  • four times
  • sixteen times
A metal road moves at a constant velocity in a direction perpendicular to its length & a constant uniform magnetic field too. Select the correct statement (s) from the following.
  • The entire rod is at the same electrical potential
  • There is an electric field in the rod
  • The electric potential is highest at the center of the rod
  • The electric potential is lowest at the center of the rod
The self inductance of a straight conductor is...
  • zero
  • very large
  • very small
  • ∞
A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A.The impedance of device is.........
  • 60Ω
  • 50Ω
  • 80Ω
  • 100Ω
The armature of dc motor has 20 Ω resistance. It draws current of 1.5 A when run by 220 V dc suppy. The value of back induced in it will be
  • 150 V
  • 190 V
  • 170 V
  • 180 V
A square loop of side 5 cm being moved right at a constant speed 2 cms–1. The front edge of it enters in magnetic field at t = 0.Fined the induced emf in the loop at t = 1s, 5s, 11s.
Physics-Electromagnetic Induction-68654.png
  • 0.3 mv, 0.3 mv, 0.3mv
  • 0, 0.3mv, 0
  • 0.3 mv, 0, 0.3 mv
  • 0, 0, 0
In the following circuit the bulb will become suddenly bright if
Physics-Electromagnetic Induction-68655.png
  • contact is made
  • contanct is broken
  • contact is made or broken
  • Won't become bright at all
The self inductance of a coil is 5H, a current of 1A changes to 2A within 5 sec. through the coil. The value of induced emf will be.......
  • 10 V
  • 0.1 V
  • 1 V
  • 100 V
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Physics Quiz Questions and Answers