Question

How does an electrostatic generator operate?

Electrons are transferred to a metallic sphere.
A motor drives a belt moving through magnets.
An electric motor causes electricity to flow through a moving belt.
Electrons are stripped off a wool pad.

Answer 1

Correct answers: 1 and 4.

Brief explanation:
- Electrostatic generators (e.g. Van de Graaff or friction machines) work by separating and transporting charge, then depositing it on a conductor (a metal sphere) so a large static potential builds up. So "Electrons are transferred to a metallic sphere" is correct.
- In many designs the belt or rubbing surfaces pick up or lose electrons by friction (triboelectric effect) — e.g. by rubbing against a wool pad — so "Electrons are stripped off a wool pad" is also a valid description of the charge-generation step.

Why 2 and 3 are wrong:
- A motor does drive the belt, but the belt moves through rollers/brushes, not magnets; magnets are not used for the electrostatic charge transfer.
- The motor supplies mechanical motion; it does not make electricity flow through the belt as a conventional current. The belt carries net static charge (not a continuous circuit current) to the sphere.