JEE Questions for Physics Electromagnetic Induction Quiz 10 - MCQExams.com

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-69232.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.
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 in direction.
  • 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.
A squre coil ABCD lying in x – y plane with it\'s centre at 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-69238.png
  • Clockwise
  • Anticlockwise
  • Alternating
  • Zero
A hundred turns of insulated copper wire are wrapped around an iron cylinder of area 1 × 10–3 m2 and are connected 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 × 10–3 C
  • 2 × 10–4 C
  • 2 × 10–5 C

Physics-Electromagnetic Induction-69241.png
  • Zero
  • 1µ V
  • 5µ V
  • 10µ V
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
A coil of Cu wire (radius–r, self-inductance – L) is bent in two concentric turns each having radius r/2. The self-inductance now
  • 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-69245.png
  • (i)
  • (ii)
  • (iii)
  • Both (ii) and (iii)
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-69247.png
  • 2)
    Physics-Electromagnetic Induction-69248.png

  • Physics-Electromagnetic Induction-69249.png

  • Physics-Electromagnetic Induction-69250.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-69252.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-69253.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-69254.png
  • BLv
  • 2BLv
  • 2πBLv

  • Physics-Electromagnetic Induction-69255.png

Physics-Electromagnetic Induction-69257.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 dosed
Physics-Electromagnetic Induction-69259.png
  • 1.25 × 10–7 A, (anticlockwise)
  • 1.25 × 10–7 A, (clockwise)
  • 2.5 × 10–7 A, (anticlockwise)
  • 2.5 × 10–7 A, (clockwise)
Two coils P and Q are placed co-axially and carry current I and I\'=0 respectively
Physics-Electromagnetic Induction-69261.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-69263.png

  • Physics-Electromagnetic Induction-69264.png
  • 2)
    Physics-Electromagnetic Induction-69265.png

  • Physics-Electromagnetic Induction-69266.png

  • Physics-Electromagnetic Induction-69267.png
The current through a coil of self-inductance L = 2 mH is given by I = t2e–t at time t.
  • 1 s
  • 2 s
  • 3 s
  • 4 s
A conducting circular loop is placed in a uniform magnetic field 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced e.m.f. in the loop when the radius is 2 cm is
  • 4.8 πμV
  • 0.8 πμV
  • 1.6 πμV
  • 3.2 πμV
Lenz\'s law is consequence of the law of conservation of
  • Charge
  • Momentum
  • Mass
  • Energy
The magnetic flux through a circuit of resistance R changes by an amount ∆ϕ in time ∆t. The total independent of quantity of electric charge Q which passes during this time through any point of the circuit is given by

  • Physics-Electromagnetic Induction-69271.png
  • 2)
    Physics-Electromagnetic Induction-69272.png

  • Physics-Electromagnetic Induction-69273.png

  • Physics-Electromagnetic Induction-69274.png
A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is
  • Equal to that due to gravity
  • Less than that due to gravity
  • More than that due to gravity
  • Depends on the diameter of the ring and the length of the magnet
A square coil of 10–2m2 area is placed perpendicular to a uniform magnetic field of intensity 103 Wb/m2. Themagnetic flux through the coil is
  • 10 weber
  • 10–5 weber
  • 105 weber
  • 100 weber
A magnet is brought towards a coil (i) speedly (ii) slowly, then the induced e.m.f./induced charge will be respecitively.
  • More in first case/More in first case
  • More in first case/Equal in both cases
  • Less in first case/More in second case
  • Less in first case/Equal in both cases

Physics-Electromagnetic Induction-69283.png
  • The rectangular, circular and elliptical loops
  • The circular and the elliptical loops
  • Only the elliptical loop
  • Any of the four loops

Physics-Electromagnetic Induction-69285.png

  • Physics-Electromagnetic Induction-69286.png
  • 2)
    Physics-Electromagnetic Induction-69287.png

  • Physics-Electromagnetic Induction-69288.png

  • Physics-Electromagnetic Induction-69289.png
The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane along the perpendicular direction. The direction of the inducedcurrent in the conducting plane will be
  • Horizontal
  • Vertical
  • Clockwise
  • Anticlockwise
A wire of length 50 cm moves with a velocity of 300 m/min, perpendicular to a magnetic field. If the e.m.f. induced in the wire is 2 V, the magnitude of thefield in tesla is
  • 2
  • 5
  • 0.8
  • 2.5
A metallic ring connected to a rod oscillates freely like a pendulum. If now a magnetic field is applied in horizontal direction, so that the pendulum now swings through the field, the pendulum will
Physics-Electromagnetic Induction-69293.png
  • Keep oscillating with the old time period
  • Keep oscillating with a smaller time period
  • Keep oscillating with a larger time period
  • Come to rest very soon
In a circuit with a coil of resistance 2 ohms, the magnetic flux changes from 2.0 Wb to 10.0 Wb in 0.2 second. The charge that flows in the coil during thistime is
  • 5.0 coulomb
  • 4.0 coulomb
  • 1.0 coulomb
  • 0.8 coulomb
The direction of induced current is such that it opposes the very cause that has produced it. This is the law of
  • Lenz
  • Faraday
  • Kirchhoff
  • Fleming
A coil of 40 Ω resistance has 100 turns and radius 6 mm is connected to ammeter of resistance of 160 ohms. Coil is placed perpendicular to the magnetic field. When coil is taken out of the field, 32 μC charge flows through it. The intensity of magnetic field will be
  • 6.55 T
  • 5.66 T
  • 0.655 T
  • 0.566 T
A magnetic field of 2 × 10–2 T acts at right angles to acoil of area 100 cm2 with 50 turns. The average e.m.f. induced in the coil is 0.1 V, when it is removed from thefield in time t. The value oft is
  • 0.1 sec
  • 0.01 sec
  • 1 sec
  • 20 sec
The total charge induced in a conducting loop when it is moved in magnetic field depends on
  • The rate of change of magnetic flux
  • Initial magnetic flux only
  • The total change in magnetic flux
  • Final magnetic flux only
A rectangular coil of 20 turns and area of cross-section 25 sq cm has a resistance of 100 ohm. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of 1000 tesla per second, the current in the coil is
  • 1.0 ampere
  • 50 ampere
  • 0.5 ampere
  • 5.0 ampere
If a coil of metal wire is kept stationary in anon-uniform magnetic field, then
  • An e.m.f. is induced in the coil
  • A current is induced in the coil
  • Neither e.m.f. nor current is induced
  • Both e.m.f. and current is induced
The magnetic flux linked with a coil, in webers, is given by the equations ϕ = 3 t2 + 4t + 9. Then the magnitude of induced e.m.f. at t = 2 second will be
  • 2 volt
  • 4 volt
  • 8 volt
  • 16 volt
A coil has an area of 0.05 m2 and it has 800 turns. It is placed perpendicularly in a magnetic field of strength 4 × 10–5Wb/m2, it is rotated through 90° in 0.1 sec. The average e.m.f. induced in the coil is
  • 0.056 V
  • 0.046 V
  • 0.026 V
  • 0.016 V
Whenever a magnet is moved either towards or away from a conducting coil, an e.m.f. is induced, the magnitude of which is independent of
  • The strength of the magnetic field
  • The speed with which of the magnet is moved
  • The number of turns in the coil
  • The resistance of the coil
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