Какво мислите за тази постановка:

Къде е уловката?

Според лекцията ще имат различни показания, което е доста контраинтуитивно.

The demo I show has become a classic - it is shown all over the world. Two identical voltmeters connected to the same 2 points in a circuit show very different values and the polarities are reversed. That's the power of Faraday’s Law which runs our entire economy. It's amazing how many people have a religious INCORRECT believe that Kirchhoff's loop rule always works. If that were true my two voltmeters should read IDENTICAL values with the same polarity but that is not the case. K’s loop rule is only valid if d(phi)/dt=0 but that is not the case here. The induced emf (Faraday!) is in the closed loop D-R2-A-R1-D. The direction of the emf at time t depends on the sign of dphi/dt at time t. That determines the direction of the E-field in the closed loop. If the the E-field is clockwise then the E-field in R2 is in the direction from D to A and the E-field in R1 is in the direction from A to D. Thus the closed loop integral of E dot dl in the loop D-R2-A-R1-D is NOT zero. The integral of E dot dl in going from D to A depends on the path; one path is through R2 and the other path is through R1. Thus the 2 voltmeters should read different values and reversed polarities. If you don’t get it, you are not alone. Occasionally I get comments from people including science teachers who want to argue with me about this demo - they clearly never FULLY understood Faraday's Law. I never argue with anyone about this as this is too basic. THIS IS THEREFORE MY ONLY RESPONSE.
By the way, in class I made the length of the wire at D zero and also of the wire at A. Thus there was only one point D and one point A and both voltmeters are attached to D and A. However, it is not at all a necessary condition that the wires at A and at D have zero length as the resistance of copper wire is much much lower than the resistances of R1 and R2. Thus my diagram on the blackboard is fine.

The oscilloscopes form a second conductive loop around the energizing coil. Although an oscilloscope is concidered to be a voltage measuring device, in this case they are measuring the current that flows in a clockwise direction around the loop that they form. The righthand oscilloscope see's current flowing into its positive terminal, the leftthand oscilloscope see's current flowing into its negitive terminal and so shows a mirror image. The different amplitude of the two displayed waveforms is caused by the different values of the resistors in parallel with the one megohm resistance of each oscilloscope. If you simply move one oscilloscope to the other side of the coil without changing the connection points of that oscilloscope, both oscilloscopes will now display the same waveform.

If you attach 2 volt meters (one on the left of1 ohm and 1 on the right of 9 ohm) then you have created 2 new loops. The current through the voltmeter left is different from the meter on the right. You can set up the 3 loops. If you assume that the the 2 outer loops are not exposed to the change B field, the closed loop integral of E dot dL in both outer loops is zero. You can then find the currents through each. Thus the voltmeters KNOW Maxwell's equations! They have no choice.

By the way, if you place the V2 voltmeter on the left (near V1) and you do NOT change any connections, cut no wires, ONLY place it to the left, then V1 and V2 will read the same value and the same polarity. Prior to 1990 I would do this demo at MIT with only 1 voltmeter and I used long wires (about 1 m long). I would start showing the students the voltage vs time (0.1 milli sec resolution) as I turned the electromagnet on when the voltmeter was placed on the right on the R2 side. Then I would repeat the demo after swinging the voltmeter over to the side of R1 (left side), I would not cut any wires and did not reconnect anything. The voltages shown with the voltmeter on the right side were positive and they were about ten times larger than those of the same voltmeter after swinging it over to the left side and the polarities were reversed.

this happens because the induced electric field is non conservative which is produced by changing magnetic field

kirichoff loop follows work done in conservative fields in closed loop is zero which is not the case in changing magnetic field

This is a perfect example of how mathematics can make physics significantly more transparent. All that needs to be said is: Kirchhoff assumes that the E field is irrotational, curl(E) =0. But Faraday's Law says that curl(E) =-dB/dt, so the E field is not conservative and the potential difference must be path dependent. It's just basic vector calculus.