Lets say I've got a rectangular conducting frame resting inside a changing uniform magnetic field.
the magnetic flux (Φ) is: the vector of the magnetic field cross product the vector of the area of the frame =>
B x A
Now let's say that the angle between the vectors is 90 so they perpendicular. so now is only |B|*|A| (the product of the lengths)
vector B pointing into the page and the frame is laying flat on the page.
Now we see the that there is a change in the magnetic flux caused by the change in the magnetic field, and this is inducing EMF (ε) in the frame. =>
ε = n * dΦ/dt
we can now define the direction of the current with Lenz's law => lets say the magnetic field is getting stronger then the direction of the current would be counter-clockwise.
but what happens if we remove one side of the frame?
Now there must be no current flowing but is there any EMF induced? any force taking place? what happens?