What is Gold Leaf Electroscope?
A gold-leaf electroscope is defined as
A type of electroscope that consists of two gold leaves is used for detecting the electrical charge of the body and for the classification of its polarity.
There are two types of electroscope:
- Gold leaf electroscope
- Pith ball electroscope
Abraham Bennet invented the gold-leaf electroscope in the year 1787. It is said that the gold leaf electroscope is more sensitive than the Pith ball electroscope.
Construction of Gold Leaf Electroscope
The gold leaf electroscope is a sensitive electroscope type that is used for detecting the charges. It consists of a brass rod with a brass disk at the top and at the bottom, there are two thin gold leaves in the form of foils. In order to keep the rod in place, the rod travels through the insulator. The charges move from the disk to the leaves through the rod. At the lower portion of the jar, a thin aluminium foil is connected. The aluminium foil is grounded with the help of a copper wire so that the leaves are protected from external electrical disruptions.
Applications of Gold Leaf Electroscope
The following are the applications of gold leaf electroscope:
- Detect charge
- Identification of the nature of the charge
- Identification of body as a conductor or an insulator
For the detection of charge, the object that needs to be tested is touched with the metal cap. If the leaves diverge, the body is said to be charged and if there is no change in the leaves of the electroscope, then the body is uncharged.
Identification of the Nature of the Charge
To identify the nature of the charge let’s consider an example. A positively charged body is brought near the metal cap. Then an unknown body is brought near the metal cap. If the leaves diverge further, we can conclude that the unknown body has a positive charge. If the leaves come closer to each other, then the charge of the unknown body is negative.
Identification of Body as a Conductor or an Insulator
To identify if a body is a conductor or an insulator, two gold leaf electroscopes are taken. One gold leaf electroscope is charged so that the leaves will diverge. Then the other gold leaf electroscope is connected to the first one. If the leaves of the other electroscope diverge, then the body is said to be a conductor and if there is no change in the leaves, the body is said to be an insulator.
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Frequently Asked Questions – FAQs
What is the name of the first electroscope?
The name of the first electroscope is vesorium. This was a pivoted needle-like electroscope invented by William Gilbert, who was a British physicist, in the year 1600.
Why is a gold leaf electroscope enclosed in a glass case?
A gold leaf electroscope is enclosed in a glass case so that the gold leaves are protected from the air. This also helps in capturing the charge leak through the air so that the sensitivity of the instrument can be increased.
What does the degree of divergence of gold leaves mean in gold leaf electroscope?
The degree of divergence of gold leaves in a gold leaf electroscope is an indicator of the amount of charge that is transferred to the gold leaves.
Why do the gold leaves in an electroscope fold back when touched with hands?
The gold leaves in an electroscope fold back when they are touched with hands because the charge is earthed.
What are 3 methods for charging objects?
The 3 methods for charging objects are friction, conduction, and induction.