Question
Question: The cause of production of eddy currents is A) The motion of a conductor in a varying magnetic fi...
The cause of production of eddy currents is
A) The motion of a conductor in a varying magnetic field.
B) The motion of an insulator in a varying magnetic field.
C) Current flowing in a conductor
D) Current flowing in an insulator
Solution
Eddy current is also known as Foucault current after the name of the scientist who first observed it. Now here we have asked the reason due to which eddy currents are produced. So here we will discuss eddy currents or Foucault currents in brief and see what is the reason behind its production.
Complete answer:
We know that the electric field lines which are created by static charges are either radially outward (if positive charge) or radially inward (if negative charge) but the induced current in a conductor is always in a circular loop. That is, if we place a metal or bulk of metal piece in a varying magnetic field then charges will flow in a loop.
These currents which are produced in a conductor or metal due to time varying magnetic flux of varying magnetic fields are called eddy currents.
Hence we can say that the motion of conductors in a varying magnetic field is the reason for the rise of eddy current.
Therefore option A is the correct answer.
Note:
It is called eddy current because the pattern in which current flows resembles the swirling eddies in water. Eddy current is given as the ratio of induced emf and resistance and we know induced emf is given as variation of magnetic flux with respect to time. So by using its formula we can that the correct answer would be A.