1. Some Conceptual Questions (1) We have discussed the idea that inductors produ
ID: 1605993 • Letter: 1
Question
1. Some Conceptual Questions
(1) We have discussed the idea that inductors produce “back emfs” andLenz’s law indicates that these oppose the changes that producethem. This can result in interesting, but complicated eects, includ-ing forces that oppose the opening of switches that break circuits.Based on this idea, which should be harder to break, an AC circuit,or a DC circuit? Why?(2) It may seem counter intuitive that increasing the resistance in anRC-circuit (the electrical analog to mechanical damping) actuallyincreases the time it takes for discharge. How do we resolve thatconfusion?(3) What are the correspondences between an LC oscillator and a me-chanical oscillator?
Explanation / Answer
that inductors produce “back emfs” andLenz’s law in
velocity acting will be on the same direction. Hence by giving the bar a slight push a very small velocity would lead to force which would increase its velocity as direction of velocity and force is same. The bar would thus accelerate with no limit to its velocity,eventually give the currents infinite speed, with the energy coming out of nowhere, thus breaking the law of conservation of energy.
a DC circuit should be hard to break as when the back emf will be produced it will try to hold the oppsieagnetic field which may cause to stop the magnetic switches to open.
As in DC there is no zero point. It is condtant magnitude. But in AC the magnitude changes and hence when it reaches zero there is no magnetic field no back emf.
Hence it can be easy to break.
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