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

Commutator's are used in

In transformer which one of the following does not change

Electricity can be transmitted overlong distances by

The induced currents setup in the core of transformer in a direction perpendicular to the flux are known as

Energy density in inductor is given by

A transformer

With the speed of motor, magnitude of black emf

The turn ratio of a step-up transformer is 4:1. If the current of 4A is passing through the primary coil. Then current in secondary coil will be

The reactance of an Inductor at 50 Hz is 100 its reactance at 100 Hz becomes

In step up transformer

The self-induction is given by

Mutual Induction has a practical role in the performance of the

A transformer is used to step up or step down

The winding of the electromagnet in motor are usually called

Lenz's law is in accordance with the Law of Conservation of

Turns ratio (r) for a step down transformer is

When motor is just started, back emf is almost

The SI unit of magnetic induction is

SI unit of self inductance is Henry which is

The Lenz's Law fulfills

The mutual inductance of a pair of coils each of N turns, is M henry. If a current of I ampere in one of the coil is brought to zero in t seconds, The average induced emf in other coil, in volt, will be

The turns ratio of a transformer is 10 it means that

The rod of unit length is moving at 30° through a magnetic field of 1 T. If velocity of rod is 1 m/s, then induced emf in the rod will be given by

Energy stores in an inductor is given by

Which of the following quantity decreases in a step-up transformer?

Lenz's law deals with

The motional emf is given by

The core of dynamo is laminated because

The devices in the circuit that consume electrical energy are known as

The main causes of power losses in a transformer are

Transformer for domestic use step down the voltage to

When the back emf in a circuit is zero, it draws

A real transformer does not change

The number of turns in a coil is increased from 10 to 100. Its self-inductance becomes

Lenz's law is in accordance with law of conservation of

In a step up transformer the turn ratio of primary and secondary coil is 1:2. A cell of 1.5V is connected across the primary coil which of the following will be voltage of secondary coil?

The mutual Inductance between two coils depends upon their

A conducting rod of length l falling with velocity V perpendicular to magnetic field B. Which of the following is potential difference between two ends

For on ideal Transformer

A device which converts low voltage or current to high voltage or current is called

The working principle of transformer is

SI unit of self inductance is Henry which is

The angular speed of rotation of the coil of A.C generator is doubled. Then induced emf will be

Self inductance does not depend upon

A step up transformer is used 120 v line to provide 240 v. If primary coil has 100 turns. The number of turns in secondary is

Lenz's law is in accordance with the Law of Conservation of

Which one of the following is not present in an A.C generator

Lenz's law is in accordance with the Law of Conservation of

The current passing through a choke coil of 5H is decreasing at the rate of 2A/s Which of the following is the emf developed across the coil?

Commentator was invented in

An increase in number of turns of a coil result in

Commutator was invented by

In transformer works on the principle of

Induction furnace based upon the concern of

B²/µo is the expression of

The self-inductance of a coil is 5H. The current changes from 1A to 2A in 5 second through the coil. Which of the following is the value of induced emf produced in the coil?

The equation for energy density is given as

The core of transformer is-made of

Which of the following quantity remain unchanged in a transformer?

A coil having number of turns N and cross sectional area A is rotated in a uniform magnetic field B with an angular velocity w. Which of the following is the maximum induced emf in it?

The energy stored in an inductor is given as

Transformer is used to change

If the speed of rotation of a generator is doubled the output voltage will be

The self inductance of solenoid is

A changing electric flux creates

If L and R denotes inductance and resistance then dimensional formula for L/R is

In step down transformer

In case of inductor, energy is stored in the

By placing soft iron inside a coil

Which one is not present in A.C generator?

Unit of self Inductance is

Eddy currents is one cause of energy loss, in

Transformer makes possible the

If the magnetic flux linked with a coil varies at the rate of 1Wb/min. Then induced emf will be

Energy density of an inductor is

In electromagnetic induction the induced emf is independent of

Henry is SI unit of

If the motor is overloaded, the magnitude of back emf

The turn ratio of a transformer is 10. It means that

The loss of energy over an A.C. cycle during the magnetization and demagnetization of transformer core is usually called

Self induced emf is sometimes called as

If the motor is overloaded then magnitude of back emf

Efficiency of transformer is not affected by

Which of the following are the power losses in a transformer?

When the motor is just started, back emf is

SI unit of mutual inductance is

When a motor is over loaded, then the magnetic of back emf

The mutual induction plays role in

A solenoid of length / meter has self-inductance L henry. If the number of turns are doubled, its self-inductance