JEE Questions for Physics Electromagnetic Induction Quiz 11 - MCQExams.com

Induced potential in a coil is developed by change of magnetic flux from 1 wb to 0.1 wb in 0.1 second is
  • 1/9 volt
  • 0.09 volt
  • 1 volt
  • 9 volt
If a copper ring is moved quickly towards south pole of a powerful stationary bar magnet, then
  • Current flows through the copper ring
  • Voltage in the magnet increase
  • Current flows in the magnet
  • Copper ring will get magnetized
In a magnetic field of 0.05 T, area of a coil changes from 101 cm2 to 100 cm2 without changing the resistance which is 2 Ω. The amount of charge that flow duringthis period is
  • 2.5 × 10–6 coulomb
  • 2 × 10–6 coulomb
  • 10–6 coulomb
  • 8 × 10–6 coulomb
A square loop of wire, side length 10 cm is placed at angle of 45° with a magnetic field that changes uniformly from 0.1 T to zero in 0.7 seconds. The induced current in the loop (its resistance is 1 Ω) is
  • 1.0 mA
  • 2.5 mA
  • 3.5 mA
  • 4.0 mA
The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was
  • Moving towards the solenoid
  • Moving into the solenoid
  • At rest inside the solenoid
  • Moving out of the solenoid
A coil of resistance 400 Ω is placed in a magnetic field. If the magnetic flux ϕ (Wb) linked with the coil varies with time t (sec) as ϕ = 50 t2 + 4. The current in the coilat t = 2 sec is
  • 0.5 A
  • 0.1 A
  • 2 A
  • 1 A
A rectangular coil ABCD is rotated anticlockwise with a uniform angular velocity about the axis shown in diagram below. The axis of rotation of the coil as well as the magnetic field B are horizontal. The induced e.m.f. in the coil would be maximum when
Physics-Electromagnetic Induction-69306.png
  • The plane of the coil is horizontal
  • The plane of the coil makes an angle of 45° with the magnetic field
  • The plane of the coil is at right angles to the magnetic field
  • The plane of the coil makes an angle of 30° with the magnetic field
An electric potential difference will be induced between the ends of the conductor shown in the diagram, when the conductor moves in the direction
Physics-Electromagnetic Induction-69308.png
  • P
  • Q
  • L
  • M
When a wire loop is rotated in a magnetic field, the direction of induced e.m.f. changes once in each
  • 1/4 revolution
  • 1/2 revolution
  • 1 revolution
  • 2 revolution
An aeroplane in which the distance between the tips of wings is 50 m is flying horizontally with a speed of 360 km/hr over a place where the vertical components of earth magnetic field is 2.0 × 10–4weber/m2. Thepotential difference between the tips of wings would be
  • 0.1 V
  • 1.0 V
  • 0.2 V
  • 0.01 V
A copper disc of radius 0.1 m is rotated about its centre with 10 revolutions per second in a uniform magnetic field of 0.1 tesla with its plane perpendicular to the field. The e.m.f. induced across the radius of disc is

  • Physics-Electromagnetic Induction-69310.png
  • 2)
    Physics-Electromagnetic Induction-69311.png

  • Physics-Electromagnetic Induction-69312.png

  • Physics-Electromagnetic Induction-69313.png
A metal conductor of length 1 m rotates vertically about one of its ends at angular velocity 5 radians per second. If the horizontal component of earth\'s magnetic field is 0.2 × 10–4 T, then the e.m.f. developed between thetwo ends of the conductor is
  • 5 mV
  • 5 × 10–4 V
  • 50 mV
  • 50 μ V
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 of the loop exists everywhere. Thecurrent induced in the loop is
Physics-Electromagnetic Induction-69316.png

  • Physics-Electromagnetic Induction-69317.png
  • 2)
    Physics-Electromagnetic Induction-69318.png

  • Physics-Electromagnetic Induction-69319.png
  • Zero
The current carrying wire and the rod AB are in the same plane. The rod moves parallel to the wire with a velocity v. Which one of the following statements is true about induced e.m.f. in the rod
Physics-Electromagnetic Induction-69320.png
  • End A will be at lower potential with respect to B
  • A and B will be at the same potential
  • There will be no induced e.m.f. in the rod
  • Potential at A will be higher than that at B
A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity ω about an axis at right angle to uniform magnetic field B. The inducede.m.f. E in the coil will be
  • NBA sin ωt
  • NB ωsin ωt
  • NB/A sin ωt
  • NBA ω sin ωt
The wing span of an aeroplane is 20 metre. It is flying in a field, where the vertical component of magnetic field of earth is 5 × 10–5 tesla, with velocity 360 km/h. Thepotential difference produced between the blades willbe
  • 0.10 V
  • 0.15 V
  • 0.20 V
  • 0.30 V
A horizontal straight conductor kept in north-southdirection falls under gravity, then
  • A current will be induced from South to North
  • A current will be induced from North to South
  • No induced e.m.f. along the length of conductor
  • An induced e.m.f. is generated along the length of conductor
A straight conductor of length 4 m moves at a speed of 10 m/s. When the conductor makes an angle of 30° with the direction of magnetic field of induction of0.1 wb. m2 then induced e.m.f. is
  • 8 V
  • 4 V
  • 1 V
  • 2 V
A circular coil of mean radius of 7 cm and having 4000 turns is rotated at the rate of 1800 revolutions per minute in the earth\'s magnetic field (B = 0.5 gauss), the maximum e.m.f. induced in coil will be
  • 1.158 V
  • 0.58 V
  • 0.29 V
  • 5.8 V
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 e.m.f. induced in the circuit in terms of B, land v, where l is the width of each tube, will be
Physics-Electromagnetic Induction-69326.png
  • Zero
  • 2)
    Physics-Electromagnetic Induction-69327.png

  • Physics-Electromagnetic Induction-69328.png

  • Physics-Electromagnetic Induction-69329.png
A 0.1 m long conductor carrying a current of 50 A is held perpendicular to a magnetic field of 1.25 mT. The mechanical power required to move the conductor witha speed of 1 ms–1 is
  • 62.5 mW
  • 625 mW
  • 6.25 mW
  • 12.5 mW
  • 125 mW
A long solenoid has 500 turns. When a current of 2 ampere is passed through it, the resulting magnetic fluxlinked with each turn of the solenoid is 4 × 10–3wb.The self-inductance of the solenoid is
  • 1.0 henry
  • 4.0 henry
  • 2.5 henry
  • 2.0 henry
An e.m.f. of 5 volt is produced by a self-inductance, when the current changes at a steady rate from 3 A to 2 A in 1 millisecond. The value of self-inductance is
  • Zero
  • 5 H
  • 5000 H
  • 5 mH
The current passing through a choke coil of 5 henry is decreasing at the rate of 2 ampere/sec. The e.m.f.developing across the coil is
  • 10 V
  • –10 V
  • 2.5 V
  • –2.5 V
Average energy stored in a pure inductance L when acurrent i flows through it, is

  • Physics-Electromagnetic Induction-69335.png
  • 2)
    Physics-Electromagnetic Induction-69336.png

  • Physics-Electromagnetic Induction-69337.png

  • Physics-Electromagnetic Induction-69338.png
A solenoid has 2000 turns wound over a length of 0.30 metre. The area of its cross-section is 1.2 × 10–3 m2. Around its central section, a coil of 300 turns is wound. If an initial current of 2 A in the solenoid is reversed in 0.25 sec, then the e.m.f. induced in the coil is
  • 6 × 10–4 V
  • 4.8 × 10–3 V
  • 6 × 10–2 V
  • 48 mV
The momentum in mechanics is expressed as m × v. The analogous expression in electricity is
  • I × Q
  • I × V
  • L × I
  • L × Q
In what form is the energy stored in an inductor
or
A coil of inductance L is carrying a steady current i. What is the nature of its stored energy.
  • Magnetic
  • Electrical
  • Both magnetic and electrical
  • Heat
The time constant of an LR circuit represents the time inwhich the current in the circuit
  • Reaches a value equal to about 37% of its final value
  • Reaches a value equal to about 63% of its final value
  • Attains a constant value
  • Attains 50% of the constant value
When the number of turns in a coil is doubled without any change in the length of the coil, its self-inductancebecomes
  • Four times
  • Doubled
  • Halved
  • Unchanged
The average e.m.f. induced in a coil in which the current changes from 2 ampere to 4 ampere in 0.05 second is 8 volt. What is the self-inductance of the coil
  • 0.1 H
  • 0.2 H
  • 0.4 H
  • 0.8 H
If a current of 3.0 amperes flowing in the primary coil is reduced to zero in 0.001 second, then the induced e.m.f. in the secondary coil is 15000 volts. The mutual inductance between the two coils is
  • 0.5 henry
  • 5 henry
  • 1.5 henry
  • 10 henry
An e.m.f. of 12 volts is induced in a given coil when the current in it changes at the rate of 48 amperes per minute. The self-inductance of the coil is
  • 0.25 henry
  • 15 henry
  • 1.5 henry
  • 9.6 henry
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 2 A flows in it, will be
  • 0.022 Wb m–2
  • 0.4 Wb m–2
  • 0.8 Wb m–2
  • 1 Wb m–2
In the following circuit, the bulb will become suddenly bright, if
Physics-Electromagnetic Induction-69349.png
  • Contact is made or broken
  • Contact is made
  • Contact is broken
  • Won't become bright at all
Two pure inductors each of self-inductance L are connected in parallel but are well separated from each other. The total inductance in
  • 2L
  • L

  • Physics-Electromagnetic Induction-69350.png

  • Physics-Electromagnetic Induction-69351.png
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
In a choke coil, the resistance XL and resistance R aresuch that
  • XL = R
  • XL>> R
  • XL<
  • XL = ∞
The number of turns of primary and secondary coils of a transformer are 5 and 10 respectively and the mutual inductance of the transformer is 25 henry. Now the number of turns in the primary and secondary of the transformer are made 10 and 5 respectively. The mutual inductance of the transformer in henry will be
  • 6.25
  • 12.5
  • 25
  • 50
A current I = 10 sin (100 π t) A is passed in first coil, which induces a maximum e.m.f. of 5 πV in second coil. The mutual inductance between the coils in
  • 5 mH
  • 10 mH
  • 15 mH
  • 20 mH
An e.m.f. of 100 millivolts is induced in a coil when the current in another nearby coil becomes 10 ampere from zero in 0.1 second. The coefficient of mutual inductionbetween the two coils will be
  • 1 millihenry
  • 10 millihenry
  • 100 millihenry
  • 1000 millihenry
A coil of self-inductance 50 henry is joined to the terminals of a battery 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 seconds
  • 50 seconds
  • 5 seconds
  • 0.5 seconds
A coil having an inductance of 0.5 H carries a current which is uniformly varying from zero to 10 ampere in 2 second. The e.m.f. (in volts) generated in the coil is
  • 10
  • 5
  • 2.5
  • 1.25
If the current is halved in a coil, then the energy stored is how much times the previous value

  • Physics-Electromagnetic Induction-69360.png
  • 2)
    Physics-Electromagnetic Induction-69361.png
  • 2
  • 4
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 LC circuit is in the state of resonance. If C = 0.1 μ F and L = 0.25 henry, neglecting ohmic resistance of circuit, what is the frequency of oscillations?
  • 1007 Hz
  • 100 Hz
  • 109 Hz
  • 500 Hz
The mutual inductance of an induction coil is 5 H. In the primary coil, the current reduces from 5 A to zero in 10–3 s. What is the induced e.m.f. in the secondary coil
  • 2500 V
  • 25000 V
  • 2510 V
  • Zero
What is the coefficient of mutual inductance when the magnetic flux changes by 2 × 10–2 Wb and change incurrent is 0.01 A
  • 2 henry
  • 3 henry

  • Physics-Electromagnetic Induction-69367.png
  • Zero
A varying current at the rate of 3A/s in a coil generates an e.m.f. of 8 mV in a nearby coil. The mutual inductance of the two coils is
  • 2.66 mH
  • 2.66 ×10–3 mH
  • 2.66 H
  • 0.266 H
If a current of 10 A flows in one second through a coil, and the induced e.m.f. is 10 V, then the self-inductanceof the coil is

  • Physics-Electromagnetic Induction-69370.png
  • 2)
    Physics-Electromagnetic Induction-69371.png

  • Physics-Electromagnetic Induction-69372.png
  • 1 H
0:0:1


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