Question

electricity and magnetism

* Watch the video below and explain what caused the whirl to span and support your explanation with equations.

https://youtu.be/z8g7jJViCZI

Answer 1

When the high voltage is transferred from the wire to the needle and then to the object, the object has sharp edges which has low surface area. Since the charge density the lower the area the more is the charge density. Since the area at the tips of the conducting wheel is very small the air gets ionised and the electrons are released which push the air causing the wheel to whirl. The alumunium conductor is placed around the device to make the spinning wheel go faster. This alumunium conductor basically catches all the electrons which are released by the spinning wheel so the air gets pushed more towards the alumunium conductor causing the wheel to spin faster. A similar concept is using in the metal brush of a Van Der Graff generator.