My attempt-
Now since the charged particle is moving it induces a magnetic field in the vicinity of the loop. So as per Lenz's Law there would be an emf induced in the loop so current would be induced having clockwise direction. But the book says the answer is option (2)
I'm not able to understand this. I would like to know where I went wrong and the correct answer.
[Physics] the direction of Induced Current in the given loop
electromagnetismhomework-and-exercises
Best Answer
Imagine the wire is infinitely long, at first. In that context it's easy to see that when the particle is far, far away from the loop, it will have practically no influence over it (i.e. the magnetic field induced by the movement of that charged particle, which is infinitely far away from the loop, wouldn't induce any current on it).
The same reasoning would work the other way around: when the particle is moving near the loop, the induced magnetic field will induce a current on the loop.
So whether the wire is infinite or not, the result is the same: as the particle approaches the loop, the influence over it increases; when it moves away from it, it decreases.
This leads to two cases:
Notice that the direction of the magnetic field is the same in both cases. It is its derivative that changes the sign, leading to the change in the direction of the current on the loop.