Notice that the voltmeter moves in response to the coil entering or leaving the magnetic gap. 2. Let's apply Faraday's Law to this situation. Faraday's Law says that the induced voltage (or emf ) in a...

Notice that the voltmeter moves in response to the coil entering or leaving the magnetic gap.

Let's apply Faraday's Law to this situation. Faraday's Law says that the induced voltage (or
emf
) in a loop of wire caused by a changing magnetic field is:

ε=dΦ/dt​

Where Φ is the magnetic flux which is

Φ=BA

In this case, the magnetic field
B
is not changing. Instead, the changing flux is due to the motion of the coil changing the field-containing area
A
as it enters or leaves the magnetic gap:

dΦ=BdA

Given that the area immersed in the gap is changing as the coil enters the gap, what is the correct expression of Faraday's Law for this situation?
That is, find the induced voltage as a function of quantities you can measure from the video.