Students are required to sketch the pattern and direction of the magnetic field produced by a direct current (d.c.) in a straight wire. Diagrams 1, 2 and 3 are three of the answers they gave. The students do not know which way the current flows in the wire. Which diagrams show patterns and directions that could be correct for the magnetic field produced by the current in the wire?
- A1, 2 and 3
- B1 and 3 only
- C1 only
- D2 only