Question

Gold Leaf Electroscope(tell about it)

Answer 1

$\Large\text{Gold Leaf Electroscope-}$

✒  Inventor of the gold-leaf electroscope:-

Englishmen Sir Abraham Bennet (1786)

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✒  Principle of a gold-leaf electroscope:-

A gold-leaf electroscope is a simple device which is used to identify the electric charge present in a body.

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✒  Construction of a gold-leaf electroscope:-

• A gold-leaf electroscope has a metallic disk attached to one end of a copper rod.

• To the other end of the copper rod, two thin gold metal leaves are attached. (Usually of gold. Can also be of another metal.)

• The side of the copper rod with the thin gold leaves is fitted inside a conical flask, through a non-conducting rubber-cork.
• The gold leaf is sealed in a glass case to prevent accidental movement induced by air currents. The stem passes through insulation so that charge cannot escape from the gold leaf.

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✒  Working of a gold-leaf electroscope:-

• Initially, electroscope is neutral as gold leaves are in relaxed position.
• When charged object (positively) brought  near the electroscope, the positive charge will move from metallic top to gold leaves. This results in the gold leaves having the same charge and therefore being repelled from each other.  
• Charges of the opposite polarity to the charged object are attracted to the terminal, while charges with the same polarity are repelled to the leaves, causing them to spread.  
• Extent of divergence depends upon the amount of charge on the electroscope.
• When the object is removed, the electroscope will continue to hold the charge.
• If the electroscope terminal is touched by a finger, the charge escapes from our body directly to the earth through our legs. The charged body thus loses its charge and becomes neutral.

Thus, to sum up, we can say that if a body on touching the disc of a gold leaf electroscope, makes its leaves diverge, then the body is charged. However, at this stage we cannot tell the nature of electric charge.

Answer 2

✒ Inventor of the gold-leaf electroscope:- Englishmen Sir Abraham Bennet (1786)

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✒ Principle of a gold-leaf electroscope:- A gold-leaf electroscope is a simple device which is used to identify the electric charge present in a body.