Summary
Highlights
To determine the direction of the force, two key pieces of information are needed: the direction of the magnetic field and the direction of the current. Fleming's left-hand rule is introduced as a method to find the force direction: the first finger points in the direction of the magnetic field (North to South), the second finger points in the direction of the current, and the thumb will then indicate the direction of the force.
An example using a horseshoe magnet and a movable rail demonstrates Fleming's left-hand rule. By aligning the first finger with the magnetic field (downwards from North to South) and the second finger with the current (towards the viewer), the thumb points to the right, indicating the direction of the force on the rail.
The strength of the force can be calculated using the equation F = BIL, where F is the force in Newtons, B is the magnetic flux density (magnetic field strength) in Teslas, I is the current in Amperes, and L is the length of the wire in meters. This formula is applicable when the wire is perpendicular to the magnetic field.
A worked example demonstrates how to use the F = BIL formula. For a 10 cm wire with a 5 amp current in a 0.4 Tesla magnetic field, the length must first be converted to meters (0.1 m). Plugging in the values (0.4 * 5 * 0.1) yields a force of 0.2 Newtons.
The video introduces the motor effect, explaining that a current-carrying wire in a magnetic field will experience a force. This occurs because the wire creates its own magnetic field, which interacts with an external magnetic field.