Use the right-hand thumb rule
Point your right thumb in the direction of current
Curl your fingers around the conductor
The curled fingers show the direction of the magnetic field
For a straight current-carrying wire, the field forms concentric circles around the wire
For a solenoid, curl your fingers in the direction of current in the coils
Your thumb points in the direction of the magnetic field inside the solenoid
Use the right-hand grip rule for circular loops and coils
For a moving positive charge, point your thumb in the direction of motion
The curled fingers show the magnetic field direction around the charge
For a current-carrying conductor in a magnetic field, use Fleming’s left-hand rule to find force direction
For a magnetic field around a magnet, field lines go from north pole to south pole outside the magnet