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A gold leaf electroscope is a device used to detect the presence and relative quantity of electric charge on a body.
- The electroscope is generally made up of a metal plate or sphere on top of a metal post (electrode) with thin foil leaves (e.g., gold) hanging from the bottom of the post.
- When the electrode is charged by induction or contact, the leaves acquire similar electric charges and repel one another due to the Coulomb force.
- Their separation directly reflects the net charge stored on them.
- To keep drafts of air away from the gold leaves, they are normally enclosed in a glass bottle or glass-walled chamber that is open at the bottom and installed above a conductive base.
- In many cases, grounded metal plates or foil strips surround the gold leaves on either side of the container.
The applications of gold leaf electroscope are:
- To identify the nature of charges.
- To detect charges.
- Identify a body as a conductor or insulator.
Very Short Answers Questions [1 Mark Questions]
Ques. Choose the correct statement.
- Gold leaf electroscope and pith ball electroscope are both equally sensitive.
- Gold leaf electroscope and pith ball electroscope are not sensitive.
- The pith ball electroscope is more sensitive than the gold leaf electroscope.
- The gold leaf electroscope is more sensitive than the pith ball electroscope.
Ans. The correct answer is d. The gold leaf electroscope is more sensitive than the pith ball electroscope.
Explanation: The gold-leaf electroscope is a more sensitive device than the pith ball or straw blade electroscopes that were in use at the time of its development.
Ques. A gold leaf electroscope does not detect the charge’s presence but tests the charge type.
- True
- False
Ans. The correct answer is b. False
Explanation: A gold leaf electroscope can detect the existence of a charge as well as test the type of charge.
Ques. A gold leaf electroscope is invented by _________ in the year of ________.
- Abraham Bennet, 1877
- John Canton, 1754
- Abraham Bennet, 1787
- John Canton, 1787
Ans. The correct answer is c. Abraham Bennet, 1787
Explanation: Abraham Bennet, a British clergyman, and scientist, invented the gold-leaf electroscope in 1787.
Ques. Name the two types of electroscopes.
Ans. The two main types of electroscopes are
- Gold leaf electroscope
- Pith ball electroscope
Ques. An electroscope is a device which is used to find whether an object is
- Hot
- Free of cracks
- Magnetic
- Charged
Ans. The correct answer is d. Charged
Explanation: An electroscope is an early scientific tool that detects the presence and magnitude of electric charge on a body. It was the first electrical measuring instrument.
Short Answers Questions [2 Marks Questions]
Ques. What is a gold-leaf electroscope?
Ans. The gold-leaf electroscope detects, measures, and determines the nature of a charge. This device operates on the principle of repulsion between similar charges.
Ques. Why is gold used as a leaf in a gold leaf electroscope?
Ans. The reasons for using gold are that it does not corrode and can be hammered to a very thin sheet. As a result, it is more sensitive to smaller electric charges. Therefore, it is the ideal material for use in an electroscope.
Ques. Why is brass used in gold leaf electroscopes?
Ans. In a gold leaf electroscope, charge is transmitted from the metal disc to the gold leaves through the metallic rod. To transmit the charge, the rod must be metallic. Wood, glass, and rubber are insulators and hence cannot be used. As a result, because brass is a metal alloy, it is used.
Ques. What is the aim of an electroscope?
Ans. We can identify the existence of charge and the type of charge in the body or substance using the scientific tool, the electroscope. Due to Coulomb's electrostatic force, a moving test object will catch the charge.
Also Read:
Long Answers Questions [3 Marks Questions]
Ques. Is a pith ball electroscope better than a gold leaf electroscope, if not why so?
Ans. The pith ball and gold leaf electroscopes are two classic types of electroscopes that are still used to explain electrostatics principles.
- The pith ball electroscope is made out of a small pith ball hung by a silk thread. When a charged body is brought close to the pith ball, part of the charges pass from the body to the ball, and the ball repels from the body, detecting charges in the body.
- The gold leaf electroscope, on the other hand, uses two golden leaves hung from a metallic tube with a plate on top. When a charged object is placed on the plate, the charges move from the tube to the leaves, which repel each other and detect charges.
Ques. How can we determine the given body as an insulator or conductor using a gold leaf electroscope?
Ans. Two gold leaf electroscopes are required to assess if the given substance is an insulator or a conductor.
- Assume the first gold leaf electroscope is charged in such a way that the leaves diverge.
- The second gold leaf electroscope is then connected to the first electroscope.
- We can say the given body is a conductor if the leaves of the second electroscope diverge. If the leaves do not alter, the body acts as an insulator.
Ques. What is the use of a gold leaf electroscope?
Ans. The following are the uses of a gold leaf electroscope
- We may use the gold leaf electroscope to detect ionizing radiation or an electric charge on a body.
- We may also use this electroscope to evaluate and contrast the quantity of charges.
- The force between two-point charges may be measured using a gold leaf electroscope.
- It may also determine the quantity and type of charges.
Very Long Answers Questions [5 Marks Questions]
Ques. What are the applications of the Gold Leaf Electroscope?
Ans. The following are the applications of the Gold Leaf Electroscope
- Detect charge: The object that has to be tested is contacted with the metal cap to detect charge. If the electroscope leaves diverge, the body is said to be charged; if there is no change in the electroscope leaves, the body is said to be uncharged.
- Identification of the nature of the charge: Consider an example to determine the nature of the charge. A positively charged body is brought in very near to the metal cap. Then an unidentified body is moved close to the metal cap. If the leaves continue to diverge, we can conclude that the unknown body is positively charged. If the leaves go closer together, the unknown body's charge is negative.
- Identification of the body as a conductor or an insulator: Two gold leaf electroscopes are used to determine if a body is a conductor or an insulator. One gold leaf electroscope has been charged, causing the leaves to diverge. The second gold leaf electroscope is then attached to the first. If the leaves of the other electroscope diverge, the body is said to be conductive; if the leaves do not change, the body is said to be an insulator.
Ques. Explain the working of the gold leaf electroscope.
Ans. A gold-leaf electroscope is used to detect the presence and determine the polarity of an electric charge in a body.
- It works on the principles of electrostatic induction and charge repulsion.
- Two thin leaves and an electrically conductive substance hang nearby and are nearly in contact with each other in this electroscope.
- Because the leaves are so thin, they lack rigidity and hang limply.
- When these leaves gain charge, they separate apart.
- The angle formed between them is determined by the amount of charge on them.
- If the instrument is insulated and the capacitance is fixed, the angle can be accurate to static voltage.
- It's worth noting that this electroscope displays potential rather than charge and that the voltage is calculated by measuring the separation angle.
Ques. What is the difference between a gold leaf electroscope and a pith ball electroscope?
Ans. The differences between a gold leaf electroscope and a pith ball electroscope are
| Pith Ball Electroscope | Gold Leaf Electroscope |
|---|---|
| It consists of a light, non-conductive ball that is generally made of plastic and hangs on a silk thread. | It is made up of two thin gold leaves that are suspended on a metal rod. |
| The pith ball is suspended in the air. | The gold leaves are enclosed in a glass vessel. |
| The charged body that will be tested is brought close to the pith ball. | The charged body to be tested is placed on the top end of the metal rod. They are not allowed to come into contact with the gold leaf. |
| The sensitivity of a pith ball electroscope is lower than that of a gold leaf electroscope. | The gold leaf electroscope has a higher sensitivity than the pith ball electroscope. |
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