Tag: ac generator

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

Dynamo converts :

  1. electric energy into magnetic energy

  2. magnetic energy into potential energy

  3. mechanical energy into electrical energy

  4. no energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The electric dynamo uses rotating coils of wire and magnetic fields to convert mechanical rotation into a pulsing direct electric current through Faraday's Law of induction (electromagnetic induction).
Multiple choice physics effects of electric current electric generator ac generator magnetic effects of electric current

Fleming's left and right hand rule are used in

  1. DC motor and AC motor

  2. DC generator and AC motor

  3. DC motor and DC generator

  4. both rules are same, any one can be used
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

DC motor is a device which coverts electrical energy into mechanical energy. It employs Fleming's left hand rule.
DC generator converts mechanical energy into electrical energy in from of DC. It employs Fleming's right hand rule.

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

Generators uses the principle of ________ to push electrons through a wire.

  1. electromagnetic induction

  2. electromagnetic reduction

  3. magnetoelectric conduction

  4. electric induction

  5. magnetic field contraction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The EMF generated by Faraday's law of induction due to relative movement of a circuit and a magnetic field is the phenomenon underlying electrical generators. When a permanent magnet is moved relative to a conductor, or vice versa, an electromotive force is created. If the wire is connected through an electrical load, current will flow, and thus electrical energy is generated, converting the mechanical energy of motion to electrical energy.

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

If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage

  1. remains unchanged

  2. reverses polarity

  3. increases

  4. decreases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Induced voltage in the rotating loop is given by   $\mathcal{E} = NBAw \ \sin wt$
where $N$ is the number of turns in the loop, $A$ is the area of the loop, $B$ is the magnetic field and $w$ is the angular speed of rotation of loop.
$\implies \ \mathcal{E}\propto w$
So, the induced voltage increases on increasing the speed of rotation of loop.

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

A device for producing electric current is ________.

  1. Ammeter

  2. Voltmeter

  3. Generator

  4. Galvanometer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Generator is the device used for the production of electric current.

It works on the principle of Faraday's laws of Electromagnetic induction in which due to the change in the magnetic flux linked with the coil there is potential induced in the coil and since the circuit is closed the current flows throw the circuit.
Generator can be AC or DC type. It is an active device and acts as the source for current.

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

Which of the following statement is correct?

  1. AC generator generates a higher voltage

  2. DC generator generates a higher voltage

  3. AC generator has a permanent magnet whereas a DC generator has an electromagnet

  4. There is a split-ring commutator in a DC generator but not in an AC generator
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The voltage generated by a generator , whether AC or DC , depends upon the rate of change of flux linked with coil .

Both type of generators usually have permanent magnets .
There is a split- ring commutator in a DC generator but an AC generator has slip - rings .
Option D is correct .