When current flows through a coil, magnetic field is generated and there will be a north and south poles on the coil.
To increase the strength of the magnetic field:
– increase the size of the current by increasing the emf of the battery
– increase the number of turns in the solenoid
– insert a soft iron core
Demonstration of Right-Hand Grip Rule (RHGR) to determine magnetic field line direction
The video below shows that as the current flows through the wire, there is a magnetic field around the wire. The compass will follow / indicate the direction of the magnetic field line. Use you RHGR to confirm the direction.
Rod Between a U-shaped Magnet
As current flows through the rod, due to the combined magnetic field of both the around the current-carrying rod and magnets, there is a force acting on the rod in the direction from a region of stronger magnetic field towards a region of weaker magnetic field around the rod.
To know the direction of the force on the rod easily, you can apply your Fleming’s Left Hand Rule.