A current-carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it, the correct statement(s) is(are)
I. The emf induced in the loop is zero if the current is constant.
II. The emf induced in the loop is finite if the current is constant.
III. The emf induced in the loop is zero if the current decreases at a steady rate.

The correct answer is: I only

A current-carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it, the emf induced in the loop is zero and the current remains constant. Hence statement I is correct.

• When a current carrying loop is kept untouched, its current will not increase or decrease.
• The flow of current increase only when a magnet gets close to the wire and create an emf.
• If the wire loop has no emf, the current won't increase and it will be stable.

• Thus the net flux always remains zero whether we increase or decrease the current.