# Electromagnetic Induction Multiple Choice Questions With Answers

The Electromagnetic Induction Multiple Choice Questions With Answers are as follows:

01. To avoid generation of heat in the cores of a transformer, the cores are made of thin metallic strips insulated from each other, known as _______ cores

02. The effective resistance or opposition to the flow of alternating current by the inductor or capacitor is called __________

03. Heat loss due to Joule Heating (also known as Ohmic or Resistive heating) is directly proportional to ____ of current.

04. Explain the Uses of Transformer for transmission of electrical energy over long distances.

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05. __________ Current comes in existence whenever electric field / flux changes with time
06. ________ transformer is used for producing large current at low voltage for electric welding.

07. Electrical Oscillations produced by exchange of energy between a capacitor which stores electrical energy and an inductor which stores magnetic energy are called ___________

08. What is Impedance Triangle?

09. __________ wave is a wave of electric and magnetic field, both varying in space and time and one being the source of other.

10. The concept of displacement current has made the laws of electricity and magnetism ____________

11. Acceptor Circuit offers _______ impedance to the current of resonant frequency

12. The production of induced emf in a coil by changing the magnetic flux associated with it is called as ________

13. In a Dead-Beat Galvanometer, the coil is mounted on copper or Aluminium frame. The ______ currents produced in these conducting frames, opposes oscillations

14. Name the Law: The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux.

15. ______ modified the Ampere’s Law to include displacement current.

16. Name the Law: The direction of the induced emf is such that it opposes the change of magnetic flux, which produces it.

17. Properties of Displacement Current is that unlike conduction current, it does not exists under ___________ conditions

18. What are the disadvantages of eddy currents?

19. Stretch the forefinger, the middle finger and the thumb, of the ____ hand mutually perpendicular to each other in such a way that the forefinger is in direction of magnetic field, middle finger in the direction of current then the thumb will indicate the direction of force acting on the conductor

20. Rejector Circuit offers _______ impedance to the current of resonant frequency

21. What is Wattless Current?

22. True or False: Rejector Circuit is a Series resonance circuit

23. Explain the principle on which Induction Furnace operate.

24. The Direction of Magnetic Field, Current (or EMF) and Force for an Electric Motor is governed by Fleming’s ___ Hand Rule

25. The total number of magnetic field lines passing normally through a given area is called _________

26. The Direction of Magnetic Field, Current (or EMF) and Force for an Electric _____ is governed by Fleming’s Right Hand Rule

27. Explain the construction, working and advantages of Choke Coil.

28. ____________ of magnetic field at a place is defined as the magnetic flux per unit area at that place.

29. _____ Circuit accepts only current of resonant frequency and rejects currents of other frequencies

30. The self-inductance of emf 1 Volt induced in the coil, when the current in the coil is changing at the rate of 1 Ampere per second is _________

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01. laminated
02. Reactance
03. square
04. To minimize Joule heating, current has to be reduced, so as to avoid heat losses while transmitting over long distances. Step-up transformer, reduces the current and increases the voltage. So electricity can be transmitted by high-tension lines, which have very high voltage, but low current. At the consumer end, step-down transformer reverts the current – voltage as desired.
05. Displacement
06. Step-down
07. LC Oscillations
08. The relation between impedance, resistance and reactance can be written as: Z² = R² + X². This is similar to Pythagoras Theorem for right angled triangle. So we can construct a right angled triangle with two sides – resistance & reactance. Then the hypotenuse will be “impedance”. So it is called “Impedance Triangle”
09. Electromagnetic
10. symmetrical
11. minimum
12. Electromagnetic Induction
13. eddy
15. Maxwell
16. Lenz’s Law
18. (a) It produces heat, (b) Heating is dangerous in some cases, and (c) It wastes energy in form of heat
19. left {Fleming’s Left Hand Rule}
20. very high
21. A circuit contains only pure inductor or a pure capacitor; resistor is zero. The phase difference between emf and current is 90°. In this case average power dissipated in circuit is zero. So the current does not perform work and is called “Idle Current” or “Wattless Current”
22. False {It is a parallel resonance circuit}
23. In induction furnace, the metal is kept on rapidly changing magnetic field. Heat generated due to eddy currents is used for melting metals
24. Left
25. Magnetic Flux
26. Generator
27. It is a Coil of large number of turns of thick insulated wire wound on insulating cylinder. They are connected in series with fluorescent tubes or mercury lamps. It opposes AC current. It controls current to maintain discharge uniform. Unlike resistors, the coil do not waste electric energy as heat. If fluorescent tube is directly connected to AC it would draw large current and would get damaged
28. Magnetic Induction (B)
29. Acceptor
30. 1 Henry