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Similar to Physics2 natural disasters an effects.pptx (20)
Physics2 natural disasters an effects.pptx
- 1. Class 8 Science Presented by: Princita Danthis 193050047
- 3. Natural phenomenon A natural phenomenon is not a man- made event. Examples include sunrise, weather, biological processes, physical processes, tidal flow, and include natural disasters such as electromagnetic pulses, volcanic eruptions, earthquakes.
- 7. ELECTRIC CHARGE It was discovered about 2500 yrs. Ago It was discovered by a Greek scientist called Thales.
- 8. How can we charge Some objects can be charged by rubbing with other objects. When objects are rubbed, they attract light objects like pieces of paper. This process is called charging by friction.
- 9. The charges acquired by rubbing are static charges. They do not move. When charges move, it is electric current. Electric current is the motion of charges through a conductor.
- 10. Types of charges • There are two types of charges. They are positive charge (+) and negative charge (-). • Two charged bodies may attract or repel each other. Like (similar) charges repel each other and unlike (dissimilar) charges attract each other.
- 12. Transfer of charge When a charged body is brought in contact with an uncharged body charges pass from the charged body to the uncharged body. This method of charging a body is called charging by contact or conduction. If a body is charged by contact it gets the same charge as the charged body.
- 14. Electroscope A device used for detecting electric charge on an object It was the first electrical measuring instrument The first electroscope, a pivoted needle called the versorium It was invented by British physician William Gilbert around 1600
- 15. A simple electroscope can be made by using an empty bottle, a piece of cardboard, a paper clip and two small strips of aluminium foil. Pass one end of the paper clip through the cardboard and hang the two aluminiun strips from the other end. If a charged body is touched to the end of the paper clip, the aluminium strips repel each other.
- 17. what we have studied • charge • types of charge • transfer of charge • electroscope
- 18. Thank you