Question

Q1 Scenario: Charge by conduction of an electroscope needle by rubbing the hard rubber rod vigorously with a sheet of wool and rub the rubber rod along the top of flat disk plate located on the top of the electroscope. Keep in mind that on the electroscope a higher needle displacement correlates to a stronger charge build up.

a) How does the electroscope needle work? Explain.

b) What is occurring to the electroscope needle as you continue to add charge? Explain.

c) Why does the needle continue to move further away as you transfer more charge? Explain.

Answer 1

Electroscope is a device to detect charge on a body.

a) working mechanism

An Electroscope has a plate on top and 2 or more needles inside a bottle like container, connected via conducting material. When a charged object is brought close to the plate, the charged object attracts the oppositely charged particles present in the plate and the like charged particles and repeled away. These like charges that were repeled from the plate gets collected in the needles, and since all the needles have same charge they repel each other.

b)

if we continue to add charge then more opposite charge will be attracted in the plate and more charges will accumulate in the needles. as a result the needles will move further and further away.

c) As more charge is been transferred to the plate, more charges will be repeled to the needles and more the charges in the needles the more is the force between them so further they move away.

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