Question

In the diagram shown, the leaves of the electroscope diverge when a positively charged rod is brought near the knob of an uncharged electroscope. The leaves diverge because:

• A. They are both negatively charged
• B. They are both positively charged
• C. One is positive and one is negative
• D. One leaf is neutral and one is positive
• E. Both leaves are neutral

Answer 1

Answer: (B)

They are both positively charged

An electroscope is a device used to detect the presence of charge and it's relative amount. If a charged object is brought near the top of the electroscope, the leaves at the bottom spread apart. The greater the charge, the farther apart they move. When a positively charged object is brought near the knob, the electrons in the leaves move towards the other end being attracted by the rod. Thus the leaves lack electrons and both become positively charged and thus push each other apart.