JEE Questions for Physics Electromagnetic Induction Quiz 6 - MCQExams.com

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-68889.png
  • 2)
    Physics-Electromagnetic Induction-68890.png
  • Zero

  • Physics-Electromagnetic Induction-68891.png
A conducting square loop of side l and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. A magnetic induction B constant in time and space, pointing perpendicular and into the plane at the loop exists everywhere with half the loop outside the field, as shown in figure. The induced e.m.f. is
Physics-Electromagnetic Induction-68892.png
  • Zero
  • RvB
  • VBl / R
  • VBl
When a circular coil of radius 1 m and 100 turns is rotated in a horizontal uniform magnetic field, the peak value of e.m.f. induced is 100V. The coil is unwound and then rewound into a circular coil of radius 2m. If it is rotated, now, with the same speed, under similar conditions, the new peak value of e.m.f. developed is
  • 50 V
  • 25 V
  • 100 V
  • 150 V
  • 200 V
A rectangular coil of 300 turns has an average area of 25 cm × 10 cm. The coil rotates with a speed of 50 cps in a uniform magnetic field of strength 4 × 102 T about an axis perpendicular of the field. The peak value of the induced e.m.f. is (in volt)
  • 3000 π
  • 300 π
  • 30 π
  • 3 π
A circular metal plate of radius R is rotating with a uniform angular velocity co with its plane perpendicular to a uniform magnetic field B. Then the e.m.f. developed between the centre and the rim of the plate is
  • πωBR2
  • ωBR2
  • πωBR2 /2
  • ωBR2 /2
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 along the magnetic north–south moves eastwards with a velocity v. The e.m.f. induced across the conductor is
  • Zero
  • B0 lv sin δ
  • B0 lv
  • B0 l v cos δ
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. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents I1, I2 and I are
Physics-Electromagnetic Induction-68896.png

  • Physics-Electromagnetic Induction-68897.png
  • 2)
    Physics-Electromagnetic Induction-68898.png

  • Physics-Electromagnetic Induction-68899.png

  • Physics-Electromagnetic Induction-68900.png
A boat is moving due east in a region where the earth\'s magnetic field is 5.0 × 10–5 NA–1m–1 due north and horizontal. The boat carries a vertical aerial 2m long. If the speed of the boat is 1.50 ms–1, the magnitude of the induced e.m.f. in the wire of aerial is
  • 1 mV
  • 0.75 mV
  • 0.50 mV
  • 0.15 mV
A circular wire of radius r rotates about its own axis with angular speed ω in a magnetic field B perpendicular to its plane, then the induced e.m.f. is

  • Physics-Electromagnetic Induction-68903.png
  • 2)
    Physics-Electromagnetic Induction-68904.png

  • Physics-Electromagnetic Induction-68905.png
  • Zero
The magnitude of magnetic induction for a current carrying toroid of uniform cross-section is
  • Uniform over the whole cross-section
  • Maximum on the outer edge
  • Maximum on the inner edge
  • Maximum at the center of cross-section
Two coils of self-inductance L1 and L2 are placed closer to each other so that total flux in one coil is completely linked with other. If M is mutual inductance between them, then

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  • 2)
    Physics-Electromagnetic Induction-68907.png

  • Physics-Electromagnetic Induction-68908.png

  • Physics-Electromagnetic Induction-68909.png
The average power dissipation in pure inductance is

  • Physics-Electromagnetic Induction-68911.png
  • 2)
    Physics-Electromagnetic Induction-68912.png

  • Physics-Electromagnetic Induction-68913.png
  • Zero
Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area A = 10 cm2 and length = 20 cm. If one of the solenoids has 300 turns and the other 400 turns, their mutual inductance is
(µ0 = 4 π × 10–7 TmA–1)
  • 4.8 π × 10–4 H
  • 4.8 π × 10–5 H
  • 2.4 π × 10–4 H
  • 4.8 π × 104 H
A 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 × 10–1 s
  • 0.3 × 10–4 s
  • 0.4 × 10–4 s
The mutual inductance between two coils is 1.25 henry. If the current in the primary changes at the rate of 80 ampere/second, then the induced e.m.f. in the secondary is
  • 12.5 V
  • 64.0 V
  • 0.016 V
  • 100.0 V
A closely wound coil of 100 turns and area of cross-section 1 cm2 has a coefficient of self-induction 1 mH. The magnetic induction in the centre of the core of the coil when a current of 2A flows in it, will be
  • 0.022 Wbm–2
  • 0.4 Wbm–2
  • 0.8 Wbm–2
  • 1 Wbm–2
Two circuits have coefficient of mutual induction of 0.09 henry. Average e.m.f. induced in the secondary by a change of current from 0 to 20 ampere in 0.006 second in the primary will be
  • 120 V
  • 80 V
  • 200 V
  • 300 V
In the following circuit, the bulb will become suddenly bright if
Physics-Electromagnetic Induction-68920.png
  • Contact is made or broken
  • Contact is made
  • Contact is broken
  • Won't become bright at all
A coil and a bulb are connected in series with a dc source, a soft iron core is then inserted in the coil. Then
  • Intensity of the bulb remains the same
  • Intensity of the bulb decreases
  • Intensity of the bulb increases
  • The bulb ceases to glow
Self-induction of a solenoid is
  • Directly proportional to current flowing through the coil
  • Directly proportional to its length
  • Directly proportional of area of cross-section
  • Inversely proportional to area of cross-section
Mutual inductance of two-coils can be increased by
  • Decreasing the number of turns in the coils
  • Increasing the number of turns in the coils
  • Winding the coils on wooden core
  • None of the above
The self-inductance of a coil is 5 henry, a current of 1 A change to 2 A within 5 second through the coil. The value of induced e.m.f. will be
  • 10 volt
  • 0.10 volt
  • 1.0 volt
  • 100 volt
The unit of inductance is
  • Volt/ampere
  • Joule/ampere
  • Volt-sec/ampere
  • Volt-ampere/sec
Self-inductance of a coil is 50 mH. A current of 1 A passing through the coil reduces to zero at steady rate in 0.1 sec, the self-induced e.m.f. is
  • 5 volts
  • 0.05 volt
  • 50 volts
  • 0.5 volt
5 cm long solenoid having 10 omh resistance and 5 mH inductance is joined to a 10 volt battery. At steady state the current through the solenoid in ampere will be
  • 5
  • 1
  • 2
  • Zero
An ideal coil of 10 henry is joined in series with a resistance of 5 ohm and a battery of 5 volt. 2 second after joining, the current flowing in ampere in the circuit will be
  • e–1
  • (1 – e–1)
  • (1 – e)
  • e
A circular coil of radius 5 cm has 500 turns of a wire. The approximate value of the coefficient of self-induction of the coil will be
  • 25 millihenry
  • 25 × 10–3 millihenry
  • 50 × 10–3 millihenry
  • 50 × 10–3 henry
In a coil of self-inductance 0.5 henry, the current varies at a constant rate from zero to 10 amperes in 2 seconds. The e.m.f. generated in the coil is
  • 10 volts
  • 5 volts
  • 2.5 volts
  • 1.25 volts
A coil of self-inductance 50 henry is joined to the terminals of a bettery of e.m.f. 2 volts through a resistance of 10 ohm and a steady current is flowing through the circuit. If the battery is now disconnected, the time in which the current will decay to 1/e of its steady value is
  • 500 sec
  • 50 sec
  • 5 sec
  • 0.5 sec
The self-inductance of a solenoid of length L, area of cross-section A and having N turns is

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  • 2)
    Physics-Electromagnetic Induction-68931.png

  • Physics-Electromagnetic Induction-68932.png

  • Physics-Electromagnetic Induction-68933.png
The self-inductance of a coil is L. Keeping the length and area same, the number of turns in the coil is increased to four times. The self-inductance of the coil will now be

  • Physics-Electromagnetic Induction-68934.png
  • L
  • 4 L
  • 16 L
The mutual inductance between a primary and secondary circuits is 0.5 H. The resistances of the primary and the secondary circuits are 20 ohms and 5 ohms respectively. To generate a current of 0.4 A in the secondary, current in the primary must be changed at the rate of
  • 4.0 A/s
  • 16.0 A/s
  • 1.6 A/s
  • 8.0 A/s
The square root of the product of inductance and capacitance has the dimension of
  • Length
  • Mass
  • Time
  • No dimension
If the current is halved in a coil, then the energy stored is how much times the previous value?

  • Physics-Electromagnetic Induction-68938.png
  • 2)
    Physics-Electromagnetic Induction-68939.png
  • 2
  • 4
An inductor of inductance L = 400 mH and resistors of resistances R1 = 2 Ω and R2 = 2 Ω are connected to a battery of e.m.f. 12 V as shown in the figure. The internal resistance of the battery is negligible. The switch S is closed at t = 0. The potential drop across L as a function of time is
Physics-Electromagnetic Induction-68941.png

  • Physics-Electromagnetic Induction-68942.png
  • 2)
    Physics-Electromagnetic Induction-68943.png

  • Physics-Electromagnetic Induction-68944.png

  • Physics-Electromagnetic Induction-68945.png
A coil of inductance 300 mH and resistance 2 Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
  • 0.15 s
  • 0.3 s
  • 0.05 s
  • 0.1 s
Which of the following is a wrong statement?
  • An e.m.f. can be induced between the ends of a straight conductor by moving it through a uniform magnetic field
  • The self-induced e.m.f. produced by changing current in a coil always tends to decrease the current
  • Inserting an iron core in a coil increases its coefficient of self-induction
  • According to Lenz's law, the direction of the induced current is such that it opposes the flux change that causes it
A coil has an inductance of 2.5 H and a resistance of 0.5 r. If the coil is suddenly connected across a 6.0 volt battery, then the time required for the current to rise 0.63 of its final value is
  • 3.5 sec
  • 4.0 sec
  • 4.5 sec
  • 5.0 sec
When the number of turns and the length of the solenoid are doubled keeping the area of cross-section same, the inductance
  • Remains the same
  • Is halved
  • Is doubled
  • Becomes four times
The mutual inductance of an induction coil is 5H. In the primary coil, the current reduces from 5A to zero in 10–3 s. What is the induced e.m.f. in the secondary coil?
  • 2500 V
  • 25000 V
  • 2510 V
  • Zero
The self-inductance of a straight conductor is
  • Zero
  • Very large
  • Infinity
  • Very small
The current in a coil changes from 4 ampere to zero in 0.1 s. If the average e.m.f. induced is 100 volt, what is the self-inductance of the coil
  • 2.5 H
  • 25 H
  • 400 H
  • 40 H
Pure inductance of 3.0 H is connected as shown below. The equivalent inductance of the circuit is
Physics-Electromagnetic Induction-68953.png
  • 1 H
  • 2 H
  • 3 H
  • 9 H
The inductance of a closed-packed coil of 400 turns is 8 mH. A current of 5 mA is passed through it. The magnetic flux through each turn of the coil is?

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  • 2)
    Physics-Electromagnetic Induction-68956.png

  • Physics-Electromagnetic Induction-68957.png

  • Physics-Electromagnetic Induction-68958.png
When the current through a solenoid increases at a constant rate, the induced current
  • Is constant and is in the direction of the inducing current
  • Is constant and is opposite to the direction of the inducing current
  • Increases with time and is in the direction of the inducing current
  • Increases with time and opposite to the direction of the inducing current
In a coil rate of change of area is 5 m2/milli second and current becomes 1 A from 2 A in 2 × 10–3 sec. If magnitude of field is 1 tesla then self-inductance of the coil is
  • 2 H
  • 5 H
  • 20 H
  • 10 H
An e.m.f. of 12 volt is produced in a coil when the current in it changes at the rate of 45 amp/minute. The inductance of the coil is
  • 0.25 henry
  • 1.5 henry
  • 9.6 henry
  • 16.0 henry
If the switch in the following circuit is turned off, then
Physics-Electromagnetic Induction-68962.png
  • The bulb B1 will go out immediately whereas B2 after sometimes
  • The bulb B2 will go out immediately whereas B1 after sometime
  • Both B1 and B2 will go out immediately
  • Both B1 and B2 will go out after sometime
Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 second, given L = 10 µ H
  • 1 V
  • 1 µV
  • 1 mV
  • 0.1 V

Physics-Electromagnetic Induction-68964.png
  • 1 sec
  • 2 sec
  • e sec
  • 2e sec
0:0:1


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