Question

In an AC generator increasing no. of turns in coil:
A) Decreases the EMF
B) EMF remains the same
C) Increases the EMF
D) EMF becomes zero

Answer 1

Hint: AC generator works based on Faraday’s law of electromagnetic induction. A conductor placed in a varying magnetic field will induce an electromotive force in the conductor. Another way is to keep the magnetic field stationary and move the conductor. An EMF is induced due to the magnetic field and the induced EMF will depend upon the no. of turns.

Formula used:
$emf=NAB\omega \sin \omega t$
Where emf is the induced EMF of the circuit, $N$ is the number of turns in the coil, $A$ is the area of the loop, $B$ is the uniform magnetic field in which the coil is placed and $\omega$ is the angular velocity of the rotor

Complete step by step solution:
AC generators work based on the principle of Faraday’s law.
According to which,
An emf is induced by the electric generators by rotating a coil in the magnetic field. When the generator coil rotates in a magnetic field, the change in the magnetic flux will induce a current in the coil.
The expression for the induced emf is given by,
$emf=NAB\omega \sin \omega t$
In this equation, $N$ stands for the number of turns in the coil. From this equation, it is clear that the EMF will increase with the increase in no of turns of the coil.

The correct answer is option (C), Increases the EMF.

Note: Other factors that influence the induced emf is the strength of the magnetic field, the Area of the rotating loop, and the angular velocity of the rotating loop. The maximum emf is obtained when $emf=NAB\omega (\because \sin \omega t=1).$