Question

A long straight current-carrying conductor has current directed from bottom to top when held vertically. What will be the direction of magnetic field lines when observed from below the conductor?

Options

A
Clockwise
B
Anti-clockwise
C
Vertically upward
D
Vertically downward

Explanation

The magnetic field generated by a long straight current-carrying conductor can be determined using the right-hand rule. When the current flows from bottom to top, if you point your right thumb in the direction of the current, your fingers will curl around the wire. When viewed from below, the fingers will curl in a clockwise direction, indicating that the magnetic field lines are oriented clockwise. The other options are incorrect because they do not represent the actual behavior of magnetic field lines around a straight current-carrying wire.

This is the correct answer. According to the right-hand rule, if you position your thumb in the direction of the current (upwards), your fingers will curl in a clockwise direction when viewed from below.

This option is incorrect. If the current flows from bottom to top, the magnetic field lines do not curl in an anti-clockwise direction when viewed from below.

This option is incorrect. The magnetic field lines do not travel vertically upward; instead, they circulate around the wire.

This option is incorrect. The magnetic field lines do not move directly downward; they are oriented in a circular pattern around the wire.