What is the Van de Graaff generator?

What is the Van de Graaff generator?

• A. A machine used to generate static electricity using a charged metal comb to induce a positive charge in a moving belt that strips electrons from a metal dome to give it a positive charge
• B. A device used to store energy indefinitely
• C. A device used to convert DC to AC
• D. A device used to measure resistance

Answer: (A)

The Van de Graaff generator is a device that generates and stores large amounts of static electricity on a hollow metal sphere. A moving insulating belt carries charge from a lower part up toward the sphere. Sharp-pointed combs near the belt and near the dome enable charge to be transferred onto the sphere’s surface, so the outer surface becomes highly charged. Those pointed contacts create corona discharge, letting charge move to or from the belt and dome with minimal direct contact, which helps the charge accumulate instead of leaking away. The result is a very high potential difference between the dome and ground, thanks to the stored charge on the dome. It’s about generating and storing static electricity, not about indefinite energy storage like a battery, nor about converting DC to AC or measuring resistance.

The Van de Graaff generator is a device that generates and stores large amounts of static electricity on a hollow metal sphere. A moving insulating belt carries charge from a lower part up toward the sphere. Sharp-pointed combs near the belt and near the dome enable charge to be transferred onto the sphere’s surface, so the outer surface becomes highly charged. Those pointed contacts create corona discharge, letting charge move to or from the belt and dome with minimal direct contact, which helps the charge accumulate instead of leaking away. The result is a very high potential difference between the dome and ground, thanks to the stored charge on the dome. It’s about generating and storing static electricity, not about indefinite energy storage like a battery, nor about converting DC to AC or measuring resistance.