- #1
AFSteph
- 17
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Hello~ I've got a confusing question;
"If a Van de Graaff generator is charged to 50,000 volts, how much energy does it take to add an additional electron to the charge on the sphere?"
(The charge of an electron is given as -1.6 x 10[itex]^{-19}[/itex]C)
My answer: (50,000 V)( -1.6 x 10[itex]^{-19}[/itex]C) = 8.0 x 10[itex]^{-15}[/itex] J
Er, I actually don't understand this at all, but if it's correct then meh.
Second question:
"How would the voltage of the generator in Part (A) compare to the voltage of a larger Van de Graaff generator with the same amount of charge? To which generator could an electron be added with the least expenditure of energy?"
According to my textbook,
BBUUUUUUUUTT... this is a bit contradictory to me because here https://www.physicsforums.com/showthread.php?t=229046 Doc Al has a different (opposite!) answer that makes sense but doesn't fit.
Can someone help me in clear English here? Thanks for any assistance!
"If a Van de Graaff generator is charged to 50,000 volts, how much energy does it take to add an additional electron to the charge on the sphere?"
(The charge of an electron is given as -1.6 x 10[itex]^{-19}[/itex]C)
My answer: (50,000 V)( -1.6 x 10[itex]^{-19}[/itex]C) = 8.0 x 10[itex]^{-15}[/itex] J
Er, I actually don't understand this at all, but if it's correct then meh.
Second question:
"How would the voltage of the generator in Part (A) compare to the voltage of a larger Van de Graaff generator with the same amount of charge? To which generator could an electron be added with the least expenditure of energy?"
According to my textbook,
So then by that reasoning, the larger generator should have more voltage for the same amount of charge. And by using the formula of volts x charge of an electron to find the energy needed to add an electron then it should take more energy to add to the bigger, higher voltage, generator.The voltage of a Van de Graaff generator can be increased by increasing the radius of the sphere or by placing the entire system in a container filled with high pressure gas.
BBUUUUUUUUTT... this is a bit contradictory to me because here https://www.physicsforums.com/showthread.php?t=229046 Doc Al has a different (opposite!) answer that makes sense but doesn't fit.
Can someone help me in clear English here? Thanks for any assistance!