Tag: physics

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Multiple choice physics effects of electric current electric generator ac generator magnetic effects of electric current

If the coil in a simple generator is wound around a soft iron core then:

  1. strength of magnetic field increases.

  2. current produced will be increased.

  3. voltage produced will be increased.

  4. all
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Voltage/current produced in a generator can be increased by: 
a) Using a powerful electromagnet to make the magnetic field stronger in place of a permanent magnet.
b) By winding the coil round a soft iron core to increase the strength of magnetic field.
c) By using a coil with more turns.
d) By rotating the coil faster.
e) By using a coil with a larger area.

Multiple choice physics effects of electric current electric generator ac generator magnetic effects of electric current

If we use a powerful electromagnet in place of permanent magnet in a generator, then:

  1. voltage produced by the generator increases.

  2. current produced by the generator increases.

  3. Both A and B are true.

  4. No effect on current or voltage occurs.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If a powerful electromagnet is used instead of a permanent magnet, magnetic field strength increases. This increase in magnetic field strength leads to the increase in induced voltage in the coil. An increased voltage leads to an increased induced current in the generator.

Multiple choice physics magnetism and electromagnetism electric generator ac generator magnetic effects of electric current

What is a commutator?

  1. A device that reverses the direction of flow of current through a circuit is called a commutator.

  2. A device that flows in the direction of flow of current through a circuit is called a commutator.

  3. A device that reverses the direction of flow of voltage through a circuit is called a commutator.

  4. All
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A device that reverses the direction of flow of current through a circuit is called a commutator. In electric motors, the split ring acts as a commutator.

Multiple choice physics effects of electric current electric generator ac generator magnetic effects of electric current

Which of the following can't increase the voltage produced by the generator?

  1. Using a powerful electromagnet to make the magnetic field stronger in place of a permanent magnet.

  2. By winding the coil round a soft iron core to increase the strength of magnetic field.

  3. By using a coil with more turns.

  4. Changing the material of the coil.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Voltage/current produced in a generator can be increased by:
a) Using a powerful electromagnet to make the magnetic field stronger in place of a permanent magnet.
b) By winding the coil round a soft iron core to increase the strength of magnetic field.
c) By using a coil with more turns.
d) By rotating the coil faster.
e) By using a coil with a larger area.