What is Fleming's left-hand rule for the direction of force on a current carrying conductor?

According to Fleming's left-hand rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular to each other. If the first finger points in the direction of magnetic field and the second finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor. Electric motor works on this principle and rotation is explained using Fleming's left-hand rule.

Describe the magnetic field produced by a solenoid carrying current.

The solenoid is a long coil having a large number of close turns of insulated copper wire. When the two ends of a solenoid are connected to a battery through a switch and current is passed through it, a magnetic field is produced around it. The magnetic field produced by a current carrying solenoid is similar to the magnetic field produced by a bar magnet. The magnetic field lines pass through the solenoid and return to the other end. The magnetic field lines inside the solenoid form parallel straight lines. This shows that the strength of the magnetic field is the same at all the points inside the solenoid. Thus, we can conclude, The magnetic field inside a long solenoid is uniform, strong and is represented by straight magnetic field lines parallel and very close to each other. The magnetic field inside a long solenoid decreases on moving towards the end of the solenoid. This is because the magnetic field lines near the ends of the solenoid start spreading out. The magnetic field outside the solenoid is weak and non-uniform. The magnetic field of the solenoid resembles the magnetic field of the bar magnet. The magnetic field lines are from South Pole to North Pole inside the solenoid and are from North Pole to South Pole outside the solenoid.