Question

Faraday's Law: What would you observe about the amplitude of an induced signal as the frequency varied? Describe whether the behavior is consistenent with Eq. 3 (Vo= w(Nd)A(Bo)cos(theta)). In particular what should your graph of amplitudes against frequencies look like according to Eq 3? In comparisons with the predictions of Eq 3, why would it be important to adjust the function generator to keep the amplitude of the B field the same at each frequency?

Answer 1

From Faraday's law, the magnitude of EMF generated (induced signal) is equal to the change in magnetic flux linked to the coil.

here, the change in flux is due to the oscillating magnetic field with frequency.

Therefore, higher the frequency of oscillating magnetic field, larger will be the amplitude of the induced signal.

if the given magnetic field is:

, then

[ Nd = number of turns in the coil]

since ,

which is frequency dependent and so the above equation is consistent with the behavior mentioned above.

This amplitude of the induced signal is also linearly dependent on the amplitude of the magnetic field and so it must be maintained constant for every frequency to remove the ambiguity of the induced signal changing due to B_o and not due to frequency.