Let a square conductor frame length $l$, resistance $R$, be pulled out with a constant velocity $\vec{v}$ from a magnetic field $\vec{B}$ perpendicular to plane of the frame, then an emf $\mathscr{E}=Blv$ is produced across the frame.
Since an induced electric field is non conservative while a non induced field is, what should be considered while calculating potential difference between any two given points in an induced field ,or will it be the same as in the latter case?
Electromagnetic Induction – Understanding the Difference Between Induced EMF and Potential Difference
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Best Answer
The EMF is around a closed loop. It is equal to the force per unit charge around the loop. So for instance $$\mathscr E=\oint_{\partial S}\left(\vec E+\vec v \times \vec B\right)\cdot d\vec \ell.$$
Your description is a bit vague. If only one part of the wire is moving, that's the part that feels a magnetic force per unit charge. If the whole thing is moving but part is in a magnetic field and the rest is not, then only the parts on the magnetic field feel a magnetic force.
Non conservative electric fields only happen when the magnetic field is changing in time. A motional EMF is from the magnetic force.
Potentials are a concept from electrostatics, in general they don't exist and in general if you try to use a son called voltmeter the reading will be affected by how much magnetic flux is going through the voltmeter and how much that flux is changing. Instead you often want to be computing the force per unit charge line integrated along the direction of the loop because that is often the analog of voltage.