physics — Electro-magnetism. class 10, ICSE board — 7-topic bundle

You know that a magnet creates a magnetic field around it. Interestingly, an electric current flowing through a conductor can also create a magnetic field. This is called the magnetic effect of electric current.

To find the direction of these magnetic field lines, you use the Right-Hand Thumb Rule:
If you hold the current-carrying wire in your right hand with your thumb pointing in the direction of the current, then the direction your fingers curl around the wire gives the direction of the magnetic field lines.