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I understand the Lenz Law is such that it tells us that the induced current must be in a direction that makes the end of the solenoid facing the magnet behave as a North Pole to repel the magnet’s North Pole thus it’s motion is opposed. Since Lenz’s law is a consequence of the principle of the conservation of energy. A magnet that is pushed into the coil is repelled. What I can’t seem to understand is the direction of the induced current. I’ve been told that the direction is clockwise, not counter clockwise. A teacher told me to use the Right Hand Grip Rule, but the way how I see it when I do it, I am seeing it in the counter clockwise direction. The question is: looking from the AC end, what is the direction of the induced current. Can someone please explain to me how the induced current is going in the clockwise direction?

enter image description here

enter image description here

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Here we have electromagnetic induction. Variable currents induce magnetic fields in loops, according to the Right Hand Grip Rule. Since the current given by the power supply is going from C to D, the magnetic field generated by left circuit goes from D to C direction. This is, looking from the coil of the C end, the magnetic field inside the solenoid is coming to you. The vector is DC orientated, meaniung the N pole is in C. Now, when this generated magnetic field is studied in our right loop/circuit, its magnetic field lines are going from A to B, because magnetic lines are closed and go back to the initial point. This is, looking from the A coil you see an entering vector arrow. So, as you said, this magnetic field is perturbing the AB solenoid and due to the Conservation of Energy, the second solenoid is preparing another magnetic field, called induced magnetic field, to counter the effects of the first magnetic field. So, how do you think this solenoid is going to do this? Well, through the flow of a second current which is the induced current. This curent does not have another alternative than going from A to B, since it is the only way it can create a magnetic field to oppose change in this second solenoid. So, looking from the coil of the AC end the induced current (i) in the second solenoid is COUNTER CLOCKWISE. The main mistake in these cases are related to the position of the hand. The thumb indicates the direction of the magnetic field when the other fingers adjust to the current direction, but it depends if the loop of the solenoid is made clockwise or counter clockwise, so be careful. Here you have your case, current going from North Pole to South Pole: enter image description here

More info: http://www.geocities.ws/motorac2002/electromagnet.htm https://theengineeringmindset.com/how-solenoids-work/right-hand-grip-rule-solenoid-coil/

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  • $\begingroup$ But if we are observing the first solenoid, the direction would be clockwise? $\endgroup$ – Mic.A Mar 18 at 4:19
  • $\begingroup$ If you are observing any of the solenoids from C or A point, you will see a counter clockwise current's direction. Current goes from positive to negative, considering the global convention. $\endgroup$ – Verifying Mar 19 at 4:22
  • $\begingroup$ Okay, I think I get it now ... So basically, the induced current is flowing in a counter clockwise direction from the AC end as it creates a magnetic field which opposes the effect of the magnetic field produced by the first coil ..? $\endgroup$ – Mic.A Mar 28 at 20:15
  • $\begingroup$ Yes, basically it is. $\endgroup$ – Verifying Mar 29 at 21:18
  • $\begingroup$ Thank you for the help $\endgroup$ – Mic.A Mar 30 at 0:29

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