Electro Magnet Induct

Question 1

What is the basic requirement for inducing emf?

Answer 1

There should be change in flux

Inducing emf requires a variation in magnetic flux linking the coil.

Question 2

The emf induced in a coil is directly proportional to what?

Answer 2

Change in flux linkages

This relationship is fundamental to electromagnetic induction.

Question 3

How can the direction of the induced emf in a conductor be determined?

Answer 3

Flemming’s Right Hand Rule

This rule is used to find the direction of induced current in generators.

Question 4

What type of emf is induced in a transformer?

Answer 4

Statically induced emf

A transformer operates based on static induction principles.

Question 5

What type of emf is induced in a DC generator?

Answer 5

Dynamically induced emf

This type of emf is generated through motion in a magnetic field.

Question 6

Inductance opposes _______ in a circuit.

Answer 6

Change in current

Inductance acts to resist changes in current flow.

Question 7

If the number of turns of a coil is increased, what happens to its inductance?

Answer 7

It increases

More turns in a coil enhance its ability to store magnetic energy.

Question 8

If the relative permeability of the material surrounding a coil is increased, what happens to the inductance of the coil?

Answer 8

It increases

Higher permeability materials enhance magnetic coupling.

Question 9

Inductance in a circuit _______ the change in current.

Answer 9

Delays

Inductance causes a lag in current changes due to stored energy.

Question 10

The inductance of a coil is _______ the reluctance of the magnetic path.

Answer 10

Inversely proportional

Lower reluctance leads to higher inductance.

Question 11

If the number of turns of a coil is increased two times, its inductance is _______.

Answer 11

Increased 4 times

Inductance increases with the square of the number of turns.

Question 12

An air cord choke is used for what application?

Answer 12

Radio frequency

Chokes are used to filter out high-frequency signals.

Question 13

If a coil has a second layer of turns, the total inductance is _______.

Answer 13

4 times

Adding layers effectively increases the inductance significantly.

Question 14

The mutual inductance is _______ the reluctance of the magnetic path.

Answer 14

Inversely proportional

Mutual inductance depends on the efficiency of magnetic coupling.

Question 15

Mutual inductance between two coils can be decreased by _______.

Answer 15

Moving them apart

Increased distance reduces the magnetic interaction between coils.

Question 16

A circuit has an inductance of 2 henry. If the circuit changes in rate of 10 m/s, then the induced emf is _______.

Answer 16

20 V

Induced emf can be calculated using Lenz’s law and Faraday’s law.

Question 17

If the current of a coil is 2 A and flux linkages are 4 W-t, what is the inductance?

Answer 17

2 H

Inductance can be calculated using the formula L = Φ/I.

Question 18

An iron coil has 10 turns and reluctance of 100 At/W. What is the inductance of the coil?

Answer 18

1 H

This is derived from the formula for inductance in terms of turns and reluctance.

Question 19

If the inductance is 2 henry and the reluctance is 200 At/W, what is the number of turns on the coil?

Answer 19

20

This can be calculated using the relationship between inductance, turns, and reluctance.

Question 20

If mutual inductance between two coils is 4 H and the current change is 2 A/s, what is the induced emf?

Answer 20

8 V

Induced emf can be calculated using the formula ε = M * (di/dt).