PHYSICS 2nd Year MCQs Chapter No.4 ELECTROMAGNETIC INDUCTION Test No.1

Lenz's law is in accordance With the law Of conservation of

The fact that emf produced by motion of a coil across a magnetic field was discovered by

The amount of torque in D.C. motors, depends upon

A device which converts mechanical energy into electrical energy is called

The induced emf lasts so long as the magnetic flux keeps

The component mainly used in a D.C. generator is

In alternating current, inductors behaves like

Faraday law is given by

A metallic ring is attached to wall of a room When the north pole of bar magnet is brought near the ring, the induced current in the ring is

The only difference between construction of D.C. generator and an A.C. generator is that of

When motor is started, the back emf is

When a motor is over loaded; then the magnitude of back emf

The current flowing through a coil due to induced emf hi it depends upon

Commutator was invented in

The device in the circuit that consumes electrical energy is called

In motional emf experiment when the system reaches an equilibrium state

A generator running in reverse may be called as

Current can be induced in a coil by changing the area of the coil in a

A motor is a device which converts electrical energy into

The, phenomenon of induced emf was observed by Faraday and Henry in

If a conductor is placed perpendicular to a magnetic field B is then motional emf will be

The emf induced by the motion of a conductor across a magnetic field is called

If back emf in a motor decreases, then it will draw

△Φ/△t has the same unit as that of

The most common source of an A.C. voltage is

Energy stored per unit volume inside the solenoid is called

The working of electric motor is reversed of

Induced current always acts to ------- the magnetic flux through the circuit

One henry is equal to

When a motor car is started its head light first becomes slight dim because the voltage across the lamp

SI unit of mutual inductance is

The ratio Of the emf induced in the secondary coil to the rate of change of current in the primary coil is known as

The inductance in a coil plays the same role in AC circuits as in ----- play in mechanics

A motor of zero back emf draws ---- current

weber / ampere is the 'unit of

The motional emf of a conductor of length L and moving perpendicular to a magnetic field B is equal to

Lenz's law deals directly with the

The SI unit of self-inductance is

The self inductance of the coil depends upon

In self induction phenomenon, the total flux through the coil is directly proportional to the ----- through the coil

If N is the number of turns in a coil, the value of self-inductance varies as

The coil used to obtain the output by mutual induction phenomenon is known as

The induced emf in a motor which opposes the applied emf running the motor is called

Alternating current generator uses

Faraday's law is based upon law of conservation of

Self inductance (L) of a coil is

The maximum emf produced by an alternating generator is

If a conductor of length 1 m is moved with velocity V across a magnetic field B at an angle of 30° with B ,then motional emf will be

The mutual inductance of coils depends upon

The working of A.C. generator is based upon the phenomenon of

Mutual inductance has a practical role in the performance of the

The phenomena by which an induced emf is produced due to change of flux is called

In D.C. generator, output of every coil is tapped only as it reaches its

The fluctuations of the output of generator can be reduced by

Which one of the following expressions for mutual inductance is correct

The energy stored in an inductor is given by

The self inductance of a coil ---- when a soft iron is placed into it

When current flows through the armature coil, the force on the conductor produces

Motional emf does not depend upon

The value, of the induced emf in a loop of wire is directly proportional to the rate of change of ------ through the loop

The principle of an electric generator is based on

In mutual induction, the coil placed with source of electric energy is called

Commutator was invented by

If the number of turns and the length of an inductor is doubled, then inductance(L) becomes

The device which is used to increase or decrease the value of alternating voltage is called

A.C current reverses its direction

If the plane of A.C. generator coil is parallel to the field, then emf induced or current in coil is

Back motor effect in generators is in accordance with law of conservation of

1 VsA^-1 =

The self-inductance of the coil is given by

In case of alternating current, the average value of current and voltage is

The mutual inductance of two coils is given by the relation

The induced emf in a rotating coil of A.C. generator varies with time

The back emf of a motor can be expressed as

The mathematical expression for self-inductance of coil is given by

If the coil is wound on an iron core, the flux through it will

The ratio of average emf in the coil to the time rate of change of current in the same coil is called

The motional emf in a conductor can be increased by

Alternating emf is produced by rotating a rectangular coil of wire in

If the plane of A.C. generator coil is perpendicular to the field, then emf induced or current in coil is

The emf induced in the coil of A.C. generator will be maximum when the angle between the plane of coil and the magnetic field is

If the length of a conductor placed parallel to magnetic field is doubled, the induced emf

The phenomenon in which changing current in a coil induces an emf in itself is called

The number of coils wound around an iron cylinder and rotated in magnetic field is called

An inductor may store energy in

It is the converse process of magnetic effect of current

If a steady current is passing though a coil then the self induced emf in it will be

The direction of the induced current in a certain coil can easily be found by using

An induced emf is produced in a circuit when