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

Commutator was invented by

Commutator was invented in

The mutual inductance of coils depends upon

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

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

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

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

Mutual inductance has a practical role in the performance of the

The mutual inductance of two coils is given by the relation

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

The self inductance of the coil depends upon

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

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

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

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

Which one of the following expressions for mutual inductance is correct

SI unit of mutual inductance is

The working of electric motor is reversed of

Faraday law is given by

The SI unit of self-inductance is

The principle of an electric generator is based on

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

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

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

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

It is the converse process of magnetic effect of current

A.C current reverses its direction

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

Lenz's law deals directly with the

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

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

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

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

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

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

In alternating current, inductors behaves like

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

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

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

1 VsA^-1 =

When motor is started, the back emf is

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

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

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

A generator running in reverse may be called as

A device which converts mechanical energy into electrical energy is called

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

Motional emf does not depend upon

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

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

An induced emf is produced in a circuit when

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

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

△Φ/△t has the same unit as that of

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

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

The self-inductance of the coil is given by

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

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

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

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

The induced emf lasts so long as the magnetic flux keeps

An inductor may store energy in

The fluctuations of the output of generator can be reduced by

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

The motional emf in a conductor can be increased by

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

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

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

The device in the circuit that consumes electrical energy is called

The energy stored in an inductor is given by

Alternating current generator uses

The back emf of a motor can be expressed as

Self inductance (L) of a coil is

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

Energy stored per unit volume inside the solenoid is called

A motor is a device which converts electrical energy into

Faraday's law is based upon law of conservation of

In motional emf experiment when the system reaches an equilibrium state

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

weber / ampere is the 'unit of

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

One henry is equal to

The maximum emf produced by an alternating generator is

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

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

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