Question

If the angular speed of the armature of a dynamo is doubled then the amplitude of the induced e.m.f will become_______.

Answer 1

Answer:

If we double the angular speed then amplitude of emf will also be double.

Explanation:

The magnetic flux through the coil is given by $\Phi =BAcos\Theta$

We know that induced emf is given by $e=-N\frac{d\Phi }{dt}$

$e=-N\frac{dBAcos\Theta  }{dt}$

$e=NBAsin\Theta \frac{d\Theta }{dt}$

$e=NBA\omega sin\Theta$

From the relation we can see that if we double the angular speed then amplitude of emf will also be double.

Answer 2

Answer: TWICE

Explanation:

amplitude= NABw

if w'=2w,

new amplitude= 2Xold amplitude.