Question

for Induction, how can you charge two neutral spheres?

a
You bring a neutral item close to a neutral sphere to make it negative.
b
You bring a negatively charged bar close to two neutral conductive spheres and the negative charge will be brought near the bar.
c
You bring a positively charged bar close to two neutral conductive spheres and the positive charge will be brought near the bar.
d
You bring a charged object, close to two neutral conductive spheres that are touching, to charge them both oppositely.

Answer 1

Correct answer: d.

Explanation in brief:
- a is wrong — a neutral object placed near a neutral sphere only polarizes it locally; it does not give the sphere a net negative charge.
- b and c are reversed — a negative rod repels electrons so the near side becomes positive; a positive rod attracts electrons so the near side becomes negative.
- d is the standard induction method: bring a charged object near two touching neutral conductors so charges separate within the connected system, then separate the spheres while the external charge is still present. Each sphere keeps the net charge it held at separation, so they end up with opposite charges.