What is the shape of magnetic field lines around a straight current-carrying conductor?

Subject: General Science

Topic: Magnetic Effects of Electric Current

Options:

1. Option A: Straight lines
2. Option B: Concentric circles
3. Option C: Ellipses
4. Option D: Parabolas

Correct Answer:

Option B: Concentric circles

Explanation:

The magnetic field lines around a straight current-carrying conductor are concentric circles centred on the wire, as observed when iron filings are sprinkled around it.