Van de Graaff generator – important questions

In one of the earlier posts, we discussed the working principle and the physical structure of the Van de Graaff generator. In this post, we will answer a few important Questions on the Van de Graaff generator.

Here are those Questions on the Van de Graaff generator with answers.

What happens if you touch the Van de Graaff generator?

If we place our hands on the upper sphere while the generator is charging it the electric charges accumulating on the sphere move onto our body as they are repelled by the other charges. When our body has enough charge our hair may stand up on end because the electric charges on the hair repel each other. We won’t be hurt because the current through our bodies is very small. Just we shouldn’t touch anything or anyone else!

What happens if you get close to a charged Van de Graaff?

The sphere on the Van de Graaff is a conductor surrounded by an insulator (the air).

While there are strong forces on the negative charges on the sphere, they’re not strong enough to break down the insulating properties of the air.

If, however, you bring another object with less negative charge close to the generator the forces on the air molecules can become strong enough to rip them apart, separating their negative electrons from the positive nuclei. A spark will jump.

If that object is your finger, you’ll feel a shock when the charges carried through the spark move through your body. While the shock can be painful, one produced by the kind of Van de Graaff in physics classrooms is not harmful.

How much charge is inside the sphere of a Van de Graaff generator?

Zero. When negative charges leave the rubber belt, they move immediately to the outer surface of the sphere. Negative charges like to be as far away from each other as possible, so they move to the outer surface of the Van de Graaff generator’s sphere.

Related study with diagrams: working principle and the physical structure of the Van de Graaff generator

Van de Graaff generator – important questions
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