Question

Lenz’s law gives
(A) Direction of current
(B) Magnitude of induced emf
(C) Magnitude of induced current
(D) Magnitude and direction of induced current

Answer 1

Hint For answering this kind of question one has to be very clear what has been asked in the question. So, for the above question it is easy because we know that Len’z law is a result of energy conservation. So, keeping that in our mind we can simply find out the correct option form the above four options.

Complete Step by step solution
Lenz law states that the current induced in the circuit due to change in the magnetic field is directed to oppose the change in the flux and to exert a mechanical force which opposes the motion.
Len’z law is also having an equation \[\varepsilon =-\frac{\partial {{\varnothing }_{B}}}{\partial t}\]
Which indicate the induced electromotive force ε and the rate of magnetic flux have opposite signs. Which means the direction of the back EMF of an induced field opposes the changing current.
Lenz's law is totally based upon the law of conservation of energy. Lenz law states that the induced current always tends to oppose the cause which produces it. So, for doing work against the opposing force one has to put the amount of effort to nullify the cause. By applying this effort to nullify the effect will lead to periodic change in the magnetic flux due to which now there will be more current which starts inducing. Thus, we can say that the extra effort which is applied to nullify the effect is just transferred into electrical energy which is nothing but the law of conservation of energy.

Therefore the option (C) is the correct option.

Note Remember the phenomena of energy conservation is one of the very important concepts in the field of physics. It is used in one or other way in physics every time. By just looking at the options one might get confused and they can start guessing but if you know the reason behind it then there will be no confusion. Try the above approach it will be very helpful for future problem solving