1.
A moving conductor coil produces an induced e.m.f. This isin accordance with
A
Coulomb's law
B
Lenz's law
C
Faraday's law
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A moving conductor coil produces an induced e.m.f. This isin accordance with
Coulomb's law
Lenz's law
Faraday's law
What is the angle made by the plane of eddy currents with the plane of magnetic lines of force?
90o
180o
0o
40o
What is the unit of inductance?
Volt-ampere/sec
Volt-sec/ampere
Volt/ampere
Joule/ampere
Which of the following is the equivalent quantity of mass in electricity?
Potential
Inductance
Current
Charge
A wire loop is rotated in a magnetic field such that the frequency of change of direction of the induced emf is
Twice per revolution
Once per revolution
Six times per revolution
Four times per revolution
Eddy currents do not cause
sparking
loss of energy
damping
heating
An e.m.f is produced in a coil, which is not connected to an external voltage source. This is not due to
the coil moving in a constant magnetic field.
the coil is stationary in external spatially varying magnetic field, which does not change with time.
the coil being in a time varying magnetic field.
the coil moving in a time varying magnetic field.
Two inductors of inductance .L each are connected in series with opposite? magnetic fluxes. The resultant inductance is (Ignore mutual inductance)
2L
3L
zero
L
When the rate of change of current is unity, the induced emf is equal to
coefficient of self inductance
total flux linked with coil
thickness of coil
number of turns in coil
If number of turns in primary and secondary coils is increased to two times each, the mutual inductance
becomes A times
remains unchanged
becomes 4 times
becomes 2 times
Identify the wrong statement.
Induction furnace uses eddy current to produce heat.
Eddy current can be used to produce braking force in moving trains.
Eddy currents are produced in a steady magnetic field.
Eddy currents can be minimized by using laminated core.
A metal plate can be heated by
placing in a space varying magnetic field, but does not vary with time.
both a and b are correct.
passing either a direct or alternating current through the plate.
placing in a time varying magnetic field.
The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?
The end A of the solenoid behaves like north pole.
The end A of the solenoid acquires positive potential.
No induced emf is developed.
The end A of the solenoid behaves like a south pole.
Which of the following does not use the application of eddy current?
Electric power meters
Induction furnace
LED lights
Magnetic brakes in trains
There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then
current is induced in the loop in the anti-clockwise direction.
current is induced in the loop in the clockwise direction.
ac is induced in the loop.
no current is induced in the loop.
A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, the current will
increase
decrease
remain same
first increase then decrease
Lenz's law is a consequence of the law of conservation of
charge
energy
induced emf
induced current
Which of the following statements is not correct?
Whenever the amount of magnetic flux linked with a circuit changes, an emf is induced in circuit.
The induced emf lasts so long as the change in magnetic flux continues.
The direction of induced emf is given by Lenz's law.
Lenz's law is a consequence of the law of conservation of momentum.
Direction of current induced in a wire moving in a magnetic field is found using
Fleming's left hand rule
Fleming's right hand rule
Ampere's rule
Right hand clasp rule
Faraday's laws are consequence of the conservation of
charge
energy
magnetic field
both b and c