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

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

Turns ratio (r) for a step down transformer is

Commentator was invented in

Efficiency of transformer is not affected by

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

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

The core of transformer is-made of

Transformer is used to change

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

Energy density in inductor is given by

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 devices in the circuit that consume electrical energy are known as

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

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

Electricity can be transmitted overlong distances by

Eddy currents is one cause of energy loss, in

Energy stores in an inductor is given by

Which of the following quantity remain unchanged in a transformer?

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

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

With the speed of motor, magnitude of black emf

When the motor is just started, back emf is

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

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

The working principle of transformer is

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

Self inductance does not depend upon

Commutator was invented by

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

Lenz's law deals with

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

SI unit of self inductance is Henry which is

In case of inductor, energy is stored in the

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

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

Henry is SI unit of

A changing electric flux creates

When motor is just started, back emf is almost

A real transformer does not change

Mutual Induction has a practical role in the performance of the

Unit of self Inductance is

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

In step down transformer

The SI unit of magnetic induction is

Transformer makes possible the

B²/µo is the expression of

Which one is not present in A.C generator?

The Lenz's Law fulfills

The equation for energy density is given as

The core of dynamo is laminated because

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

In electromagnetic induction the induced emf is independent of

An increase in number of turns of a coil result in

In step up transformer

By placing soft iron inside a coil

For on ideal Transformer

If the motor is overloaded, the magnitude of back emf

SI unit of mutual inductance is

The energy stored in an inductor is given as

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?

Induction furnace based upon the concern of

The self-induction is given by

The mutual Inductance between two coils depends upon their

Commutator's are used in

A transformer is used to step up or step down

Energy density of an inductor is

Transformer for domestic use step down the voltage to

The motional emf is given by

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

In transformer which one of the following does not change

Self induced emf is sometimes called as

A transformer

The mutual induction plays role in

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

The main causes of power losses in a transformer are

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

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

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

Lenz's law is in accordance with the 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?

If the motor is overloaded then magnitude of back 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 turns ratio of a transformer is 10 it means that

In transformer works on the principle of

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

The self inductance of solenoid is

SI unit of self inductance is Henry which is

The winding of the electromagnet in motor are usually called

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?