"Potential difference" is not the same as "induced emf" (often called "induced voltage"). The potential difference (difference in the electric scalar potential) between two points A and B is independent of the path we take from A to B. If a voltmeter always measured the potential difference between A and B, then the position of the voltmeter would make no difference. However, it is quite possible for the measurement by a voltmeter between points A and B to depend on the position of the voltmeter, if a time-dependent magnetic field is present. For example, consider an infinitely long solenoid using an AC current to generate a varying flux in the interior of the solenoid. Outside the solenoid we have two resistors connected in a ring around the solenoid. The resistor on the left is 100 Ω and the one on the right is 200 Ω, they are connected at the top and bottom at points A and B. The induced voltage, by Faraday's law is V , so the current I = V / ( 100 + 200 ) . Therefore, the voltage across the 100 Ω resistor is 100 I and the voltage across the 200 Ω resistor is 200 I , yet the two resistors are connected on both ends, but V A B measured with the voltmeter to the left of the solenoid is not the same as V A B measured with the voltmeter to the right of the solenoid.