Question

Consider an experiment where Electric current is flowing in a wire. It is observed that clockwise magnetic field is produced around the wire. A teacher decides to reverse the direction of source battery which results in reversal of electrical current. What will be the effect on magnetic field?

• A. Magnetic field disappears
• B. Direction of field lines reverse
• C. Field lines changes direction to parallel to wire
• D. None of the above

Answer 1

The correct option is B Direction of field lines reverse

The direction of magnetic field produced by current carrying wire depends on the direction of current in wire.” Magnetic field pattern due to straight current carrying conductor are concentric circles whose center lie on the wire. The direction of magnetic field due to straight current carrying conductor can be determined by Right hand thumb rule.

Using Right Hand thumb rule, as current direction reverses, you need to reverse the hand and direction of magnetic field reverses.