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A positively charged glass rod is brought close to the disc (cap) of an initially uncharged gold-leaf electroscope, and the two leaves spread apart. Which statement is correct?

1. There is no charge on the leaves
2. A positive charge is induced on the leaves
3. A negative charge is induced on the leaves
4. One leaf becomes positively charged and the other negatively charged

Correct answer: A positive charge is induced on the leaves

Solution

The positive rod attracts free electrons in the conductor toward the cap, leaving the two leaves with a net positive charge. Both leaves carry the same sign, repel each other, and diverge. Net charge of the isolated electroscope stays zero.

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