Explain the principle of gold-leaf electroscope with a schematic diagram.

What is the charge on the gold leaf of the electroscope shown in the figure alongside?

Solve the following crossword puzzle with the help of the clues given below.

Across
2. Unlike charges ____ each other.
4. The origin of an earthquake
7. The point on the Earth's surface directly above the origin of the earthquake
8. The magnitude of an earthquake is measured in ____ scale.
9. The process of connecting a charged body to the Earth
10. Sudden shake on the surface of the Earth

Down
1. A material that allows the flow of charges through it
3. In the process of charging by ____, the uncharged body acquires the same kind of charge.
5. Like charges ____ each other.
6. Device used to measure the intensity of an earthquake.