Question

current carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it. The correct statement(s) is (are)
This question has multiple correct options
A. The emf induced in the loop is zero if the current is constant.
B. The emf induced in the loop is finite if the current is constant.
C. The emf induced in the loop is zero if the current decreases at a steady rate.
D. The emf induced in the loop is finite if the current decreases at a steady rate

Answer 1

Hint: The most important concepts of electricity are the Faraday’s law of magnetic induction. It describes the induction of emf in a conductor and calculates the emf produced in the conductor which comes across at the way of changing magnetic fields and causes the flow of current in the wires.

Complete step by step answer:Magnetic flux generates the magnetic field around the magnetic material. The generated magnetic flux induced in the magnetic field by the wire is in upwards in the left direction and is downwards in the right direction of the wire and as a result, the net flux always remains the zero in case of the increase or decrease in the current source.
$\therefore \phi = 0$
Thus, the induced emf is zero.
$\dfrac{{d\phi }}{{dt}} = 0$
Therefore the required answer is - A current carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it then the emf induced in the loop is zero if the current is constant and the emf induced in the loop is zero if the current decreases at a steady rate.
Hence, from the given multiple choices- the options (A) and (C) are the correct answers.

Note:Remember the difference between the Lenz’s and Faraday's law. Lenz’s law states the direction of the current flow. Faraday’s law relates to the rate of change of the magnetic flux through the magnitude of the electromagnetic force induced in the loop.