Questions on Van de Graaff Generator

[sniffer]

a few questions:

1. in van de graaff generator, is the sphere positive?

2. what will happen if we shorten the rubber band conveyor? to make the generator smaller and portable.

3. why does it maintain constant current when connected to a load? why doesn't the current decrease?

 

[Doc Al]

1. The rubber imparts a negative charge to the sphere.

2. I would imagine that the less rubber you have, the harder it will be to build up a charge.

3. Realize that you are imparting a charge to the sphere at some rate. When you connect the sphere to a load, that charge can discharge through the load creating a current. As long as you keep adding charge, why wouldn't the current remain the same (once a steady state is reached)?

 

[GSXR750]

1. Yes, the sphere in a Van de Graaff generator is typically positively charged. This is because the generator works by transferring positive charges from the bottom to the top of the sphere, creating a high voltage difference between the two points.

2. Shortening the rubber band conveyor in a Van de Graaff generator would decrease the overall size and portability of the generator. However, it may also affect the efficiency and output of the generator. The length of the conveyor is carefully designed to ensure maximum charge accumulation and transfer, so shortening it may result in a weaker or less effective generator.

3. A Van de Graaff generator maintains a constant current when connected to a load because the generator is designed to continuously transfer charges from the bottom to the top of the sphere. This transfer of charges creates a constant flow of current in the circuit. Additionally, the generator is designed to maintain a high voltage difference, which helps to keep the current from decreasing.