JEE Questions for Physics Electromagnetic Induction Quiz 14 - MCQExams.com

A square loop of side 5 cm enters a magnetic field with 1 cms–1. The front edge enters the magnetic field att = 0, then which graph best depicts e.m.f
Physics-Electromagnetic Induction-69552.png

  • Physics-Electromagnetic Induction-69553.png
  • 2)
    Physics-Electromagnetic Induction-69554.png

  • Physics-Electromagnetic Induction-69555.png

  • Physics-Electromagnetic Induction-69556.png
A magnet is made to oscillate with a particular frequency, passing through a coil as shown in figure. The time variation of the magnitude of e.m.f. generatedacross the coil during one cycle is
Physics-Electromagnetic Induction-69558.png

  • Physics-Electromagnetic Induction-69559.png
  • 2)
    Physics-Electromagnetic Induction-69560.png

  • Physics-Electromagnetic Induction-69561.png

  • Physics-Electromagnetic Induction-69562.png
A metallic ring is dropped down, keeping its plane perpendicular to a constant and horizontal magnetic field. The ring enters the region of magnetic field at t = 0 and completely emerges out at t = T sec. Thecurrent in the ring varies as

  • Physics-Electromagnetic Induction-69563.png
  • 2)
    Physics-Electromagnetic Induction-69564.png

  • Physics-Electromagnetic Induction-69565.png

  • Physics-Electromagnetic Induction-69566.png
Which of the following figure correctly depicts the Lenz\'s law. The arrows show the movement of the labelled pole of a bar magnet into a closed circular loop and the arrows on the circle show the direction of the induced current

  • Physics-Electromagnetic Induction-69567.png
  • 2)
    Physics-Electromagnetic Induction-69568.png

  • Physics-Electromagnetic Induction-69569.png

  • Physics-Electromagnetic Induction-69570.png
The current i in a coil varies with time as shown in the figure. The variation of induced e.m.f. with time would be
Physics-Electromagnetic Induction-69572.png

  • Physics-Electromagnetic Induction-69573.png
  • 2)
    Physics-Electromagnetic Induction-69574.png

  • Physics-Electromagnetic Induction-69575.png

  • Physics-Electromagnetic Induction-69576.png
The current (I) in the inductance is varying with time according to the plot shown in figure.
Which one of the following is the correct variation of voltage with time in the coil
Physics-Electromagnetic Induction-69578.png

  • Physics-Electromagnetic Induction-69579.png
  • 2)
    Physics-Electromagnetic Induction-69580.png

  • Physics-Electromagnetic Induction-69581.png

  • Physics-Electromagnetic Induction-69582.png
Assertion Eddy current is produced in any metallic conductor when magnetic flux is changed around it.
Reason Electric potential determines the flow of charge.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The quantity L/R possesses dimensions of time.
Reason To reduce the rate of increase of current through a solenoid, we should increase the time constant (L/R).
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Faraday\'s laws are consequence of conservation of energy.
Reason In a purely resistive ac circuit, the current lags behind the e.m.f. in phase.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true.
Assertion Only a change in magnetic flux will maintain an induced current the coil.
Reason The presence of large magnetic flux through a coil maintains a current in the coil, if the circuit is continuous.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion In electric circuits, wires carrying currents in opposite directions are often twisted together.
Reason If the wires are not twisted together, the combination of the wires forms a current loop, The magnetic field generated by the loop might affect adjacent circuits or components
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The induced e.m.f. and current will be same in two identical loops of copper and aluminium when rotated with same speed in the same magnetic field.
Reason Induced e.m.f. is proportional to rate of change of magnetic field while induced current depends on resistance of wire.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Inductance coil are made of copper.
Reason Induced current is more in wire having less resistance.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion When two coils are wound on each other, the mutual induction between the coils is maximum.
Reason Mutual induction does not depend on the orientation of the coils.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Electromagnetic Induction-69585.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true
Assertion An aircraft flies along the meridian, the potential at the ends of its wings will be the same.
Reason Whenever there is change in the magnetic flux e.m.f. induces.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
A coil of inductance 8.4 mH and resistance 6Ω is connected to a 12 V battery. The current in the coil is 1A in the time..........
  • 500 sec
  • 20 sec
  • 35 ms
  • 1 ms
Assertion A spark occurs between the poles of a switch when the switch is opened.
Reason Current flowing in the conductor produces magnetic field.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion In the phenomenon of mutual induction, self-induction of each of the coils persists.
Reason Self-induction arises when strength of current in same coil changes. In mutual induction, current is changing in both the individual coils
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Lenz\'s law violates the principle of conservation of energy.
Reason Induced e.m.f. always opposes the change in magnetic flux responsible for its production.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The back e.m.f. in a dc motor is maximum when the motor has just been switched on.
Reason When motor is switched on it has maximum speed.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An induced e.m.f. is generated when magnet is withdrawn from the solenoid.
Reason The relative motion between magnet and solenoid induces e.m.f.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An artificial satellite with a metal surface is moving above the earth in a circular orbit. A current will be induced in satellite, if the plane of the orbit is inclined to the plane of the equator.
Reason The current will be induced only when the speed of satellite is more than 8 km/sec.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An electric motor will have maximum efficiency when back e.m.f. is equal to applied e.m.f.
Reason Efficiency of electric motor is depends only on magnitude of back e.m.f.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A metal piece and a non-metal (stone) piece are dropped from the same height near earth\'s surface. Both will reach the earth\'s surface simultaneously.
Reason There is no effect of earth\'s magnetic field on freely falling body.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A transformer cannot work on dc supply.
Reason dc changes neither in magnitude nor indirection.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Soft iron is used as a core of transformer.
Reason Area of hysteresis loop for soft iron is small.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion An ac generator is based on the phenomenon of self-induction.
Reason In single coil, we consider self-induction only.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Electromagnetic Induction-69588.png
  • (ec= ed)< (ea = eb)
  • (ec= ed)> (ea = ed)
  • ec>ed> eb> ea
  • ecd< eba
A circular coil and a bar magnet placed near by are made by move in the same direction. The coil covers a distance of 1 m in 0.5 sec and the magnet a distance of2 m in 1 sec. The induced e.m.f. produced in the coil
  • Zero
  • 1 V
  • 0.5 V
  • Cannot be determined from the given information
A square coil ABCD lying in x –y plane with it\'s centreat origin. A long straight wire passing through origin carries a current i = 2t in negative z – direction. The induced current in the coil is
Physics-Electromagnetic Induction-69591.png
  • Clockwise
  • Anticlockwise
  • Alternating
  • Zero
A hundred turns of insulated copper wire are wrapped around an iron cylinder of area 1 × 10–3 m1 and areconnected to a resistor. The total resistance in the circuit is 10 ohms. If the longitudinal magnetic induction in the iron changes from 1 weber m–2, in one direction to 1 weber m–2 in the opposite direction, how much charge flows through the circuit
  • 2 × 10–2 C
  • 2 × 10–3C
  • 2 × 10–4 C
  • 2 × 10–5C

Physics-Electromagnetic Induction-69594.png
  • Zero
  • 1 μ V
  • 5 μV
  • 10 μV
An aircraft with a wing-span of 40 m flies with a speed of 1080 km h–1 in the eastward direction at a constant altitude in the northern hemisphere, where the vertical component of earth\'s magnetic field is 1.75 × 10–5T.Then the e.m.f. that develops between the tips of the wings is
  • 0.5 V
  • 0.35 V
  • 0.21 V
  • 2.1 V

Physics-Electromagnetic Induction-69597.png
  • 2L
  • L
  • 4L
  • L/2
In which of the following circuit is the current maximum just after the switch S is closed
Physics-Electromagnetic Induction-69599.png
  • (i)
  • (ii)
  • (iii)
  • Both (ii) and (iii)

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  • 2)
    Physics-Electromagnetic Induction-69676.png

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  • Physics-Electromagnetic Induction-69678.png
A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is n and the cross-sectional area of the coil is A. When the coil turns through 180° about its diameter, the charge flowing through the coil is Q. The total resistance of the circuit is R. What is the magnitude of the magnetic induction

  • Physics-Electromagnetic Induction-69601.png
  • 2)
    Physics-Electromagnetic Induction-69602.png

  • Physics-Electromagnetic Induction-69603.png

  • Physics-Electromagnetic Induction-69604.png
Two circular coils A and B are facing each other as shown in figure. When the current i through A is altered
Physics-Electromagnetic Induction-69606.png
  • There will be repulsion between A and B if i is increased
  • There will be attraction between A and B if i is increased
  • There will be neither attraction nor repulsion when i is changed
  • Attraction or repulsion between A and B depends on the direction of current. It does not depend whether the current is increased or decreased
A conducting loop having a capacitor is moving outward from the magnetic field then which plate of the capacitor will be positive
Physics-Electromagnetic Induction-69607.png
  • Plate–A
  • Plate–B
  • Plate–A and Plate –B both
  • None of the above
A straight wire of length L is bent into a semicircle. It is moved in a uniform magnetic field with speed v with diameter perpendicular to the field. The induced e.m.f.between the ends of the wire is
Physics-Electromagnetic Induction-69608.png
  • BLv
  • 2BLv
  • 2πBLv

  • Physics-Electromagnetic Induction-69609.png

Physics-Electromagnetic Induction-69611.png
  • 2 H
  • 5 H
  • 20 H
  • 10 H
The magnetic field in the cylindrical region shown in figure increases at a constant rate of 20 mT/sec. Each side of the square loop ABCD has a length of 1 cm and resistance of 4 Ω. Find the current in the wire AB if the switch S is closed
Physics-Electromagnetic Induction-69613.png
  • 1.25 × 10–7 A, (anti-clockwise)
  • 1.25 × 10–7 A, (clockwise)
  • 2.5 × 10–7 A, (anti clockwise)
  • 2.5 × 10–7 A, (clockwise)
Two coils P and Q are placed co-axially and carry current I and I\' respectively
Physics-Electromagnetic Induction-69615.png
  • If I' = 0 and P moves towards Q, a current in the same direction as I is induced in Q
  • If I = 0 and Q moves towards P, a current opposite in direction to that of I' is induced in P
  • When I ≠0 and I' ≠0 are in the same direction, then two coil tend to move apart
  • None of the above
A pair of parallel conducting rails lie at right angles to a uniform magnetic field of 2.0 T as shown in the fig. Two resistors 10 Ω and 5 Ω are to slide without friction along the rail. The distance between the conducting rails is 0.1 m. Then
Physics-Electromagnetic Induction-69617.png

  • Physics-Electromagnetic Induction-69618.png
  • 2)
    Physics-Electromagnetic Induction-69619.png

  • Physics-Electromagnetic Induction-69620.png

  • Physics-Electromagnetic Induction-69621.png
The current through a coil of self-inductance L = 2 mH is given by I = t2e–t at time t. How long it will take tomake the e.m.f. zero
  • 1 s
  • 2 s
  • 3 s
  • 4 s
A conducting wire sits on smooth metal rails, as shown in figure. A variable magnetic field points out of the page. The strength of this magnetic field is increased linearly from zero. Immediately after the field starts to increase, what will be the direction of the current in the wire and the direction of the wire's motion ?
Physics-Electromagnetic Induction-69624.png
  • Current in the wire = North , Motion of the wire = No motion
  • Current in the wire = North , Motion of the wire = East
  • Current in the wire = South , Motion of the wire = West
  • Current in the wire = South , Motion of the wire = East
A rectangular loop has a sliding connector PQ of length l and resistance R Ω and it is moving with a speed v as shown in the figure. The set up is placed in an uniform magnetic field going into the plane of the paper. The three currents I1 , I2 , I are
Physics-Electromagnetic Induction-69626.png

  • Physics-Electromagnetic Induction-69627.png
  • 2)
    Physics-Electromagnetic Induction-69628.png

  • Physics-Electromagnetic Induction-69629.png

  • Physics-Electromagnetic Induction-69630.png
A rectangular loop of length 1 and breadth b is placed at distance of x from infinitely long wire carrying current i such that the direction of current is parallel to breadth. If the loop moves away from the current wire in a direction perpendicular to it with a velocity v, the magnitude of the emf in the loop is ( μ0 = permeability of free space)

  • Physics-Electromagnetic Induction-69632.png
  • 2)
    Physics-Electromagnetic Induction-69633.png

  • Physics-Electromagnetic Induction-69634.png

  • Physics-Electromagnetic Induction-69635.png
One conducting U-tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant speed v, then the emf induced in the circuit in terms of B, l and v, where l is the width of each tube, will be
Physics-Electromagnetic Induction-69637.png
  • Blv
  • -Blv
  • zero
  • 2 Blv
0:0:1


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