Suppose an electroscope is electrically neutral. Can this neutral electroscope be used to determine wether the net charge on an object is positive or negative?

Question

ybarrap · Answer

Yes. First touch the electroscope with an object that has a known polarity, positive or negative. For example with cat fur or with a rubber stick, both of which produce opposite charges.

The effect will be a separation between two segments on the electroscope:

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Next, take the sample you wish to test the polarity of and touch the electroscope with it. If the separation gets bigger, then the sample is of the same polarity as the 1st object. If the separation gets smaller, then sample is of opposite polarity.

Does this make sense?