Question
State Fleming’s left-hand rule. Describe Barlow’s wheel experiment.
Answer
Fleming’s left-hand rule: It states that if you extend your thumb, forefinger, and middle finger of your left hand so that they are all perpendicular to each other, and the forefinger points in the direction of the magnetic field, and the middle finger points in the direction of the current in the conductor, then your thumb will point in the direction of the force on the conductor.
Barlow’s wheel experiment is a classical demonstration of the interaction between electricity and magnetism. It was first performed by Peter Barlow in 1822 to demonstrate the principles of electromagnetic induction.
The experiment involves a copper disk, known as Barlow’s wheel, which is mounted on an axle and rotated by a belt connected to a power source. The wheel has a series of copper spokes extending radially from its centre, and a magnet is placed near the rim of the wheel so that it can exert a force on the spokes as they pass by.
When an electric current is passed through the spokes of the wheel, it creates a magnetic field around them. As the spokes pass by the magnet, they experience a force that causes the wheel to rotate. The rotation of the wheel can be observed and measured, and it demonstrates the principle of electromagnetic induction, which is the generation of an electric current in a conductor due to a changing magnetic field.
