Describe gold leaf elecroscope and explain how it is used to detect a charge
Answers
Move the charged object near the top terminal of the electroscope. Do NOT move it so close that it transfers charge.
If the object has a positive charge, it will pull electrons up to the top terminal. This will cause the leaves of the electroscope to be more positively charged, causing them to move further apart.
If the object has a negative charge, it will repel electrons from the top terminal. This pushes electrons down to the leaves, causing them to be less positively charged, causing them to drop towards each other. If the object has a much larger negative charge than the positive charge on the electroscope, as you move it closer the leaves will drop to touch, then begin to rise again as so many electrons will be repelled from the top plate that there are now more negative charges than positive in the leaves and they will repel again.
Observe this as you are moving the charged object towards the top terminal of the positively charged electroscope. If you get close enough for some charge to leak over, things will change, so you want to watch for the first change in position of the leaves of the electroscope.
This movement of charge without actually transferring charged particles is called electrostatic induction, not to be confused with electromagnetic induction.
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