Question

A Dynamo produces an electric current. It is based on which principle:
A. Magnets have attractive property
B. Conductors carrying current behave like magnets
C. Electromagnetic induction
D. None of there

Answer 1

Hint: Dynamo or electric generator is used to generate electrical energy from mechanical motion.
It is based on the principle that when there is a motion of a conductor within a constant magnetic field, an electromotive force is generated in it due to which a current starts flowing in it.
This takes place due to change in magnetic flux passing through the conductor and hence a current is induced in it which can be used as dynamo’s output.

Complete step by step answer:
The generation of electricity by a dynamo is based on a principle called electromagnetic induction. When the lines of force that pass from the north to the south pole of a magnet are cut by a wire there is produced or induced in the wire current of electricity.
In Dynamo, a coil of wire is placed between a strong magnet and when it is rotated by mechanical force the flux passing through it changes as it cuts the magnetic lines of force and hence there is development of electromotive force and a current start running through it.it is based on faraday’s law of electromagnetic induction.
The strength of a current in electromotive force set up by induction depends upon some factors which are the strength of the magnet, the number of turns of wire in the coil or loop, and the speed with which the magnetic lines of force are cut, that is, the speed at which the coil rotates.

So, the correct answer is “Option C”.

Note: The direction of induced current is dependent on the direction of motion of the main coil and the direction of magnetic lines of force and is determined by Fleming’s rule.
When a loop of wire rotates in a magnetic field, the magnetic flux through it, and thus the potential induced in it, reverses with each half turn, generating an alternating current ,to prevent and obtain direct current ,we use commutators in Dynamo.