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# Electric field watch

1. Hey could someone help please im stuck on this question.

There is two horizontal contucting plates the top plate is positively charged and the bottom is negatively charged, there is a constant voltage, creating a uniform electric field.

A very small, negatively-charged, polystyrene sphere is introduced between the plates. It is found that the values of the weight of the sphere, the charge on it and the electric field between the plates are such as to cause the sphere to remain stationary

At time t=0 the upper plate starts to move with uniform velocity towards the lower plate. the voltage between the plates is kept constant, and the plates remain parallel throughout the motion.

Describe what happens to the charged sphere while the upper plate is moving.

thanx
2. thanx
3. the didtance between the plates falls, the electric field therefore grows stronger and the polystyrene ball accelerates uward toward the top plate.
4. If I remember correctly it will then become positively charged, be repelled from the positive plate to the negative plate. The ball will then become negatively charged and be repelled from the negative plate to the positive plate and so on and so on.

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