Please post detailed solution.

# Doubt in Magnetic effects of current

Using ampere’s law

Assuming current is uniform over cross section

The current flowing inside the area of loop is I/4.

If anyone find anything wrong pls do say me.

I'm so sorry but I didn't get you. Can we apply Amperes law like that? The answer is correct btw.

Yes ..we are only concerned with current enclosed(assuming it’s uniform over area) so we took I/4....(for whole area it’s I and for one fourth of the area which is inside the loop the current flowing is I/4)

Any doubts pls ask again

Yea, this seems right, however, the question does consider that the wire is a thin wire (0 area). So you'll have to take radius of the wire tending to zero.

Another intuitive way to think about this is to make the square larger, with the center as the wire itself, and then divide into 4 equal quadrants. Each of the squares will have same value of the integral, and hence one individual square will be 1/4th the total.