Ls 發問於 科學及數學物理學 · 4 年前

Please help. Big confusion about potential. Urgent.?

My book said the dome of a van de Graff generator had a very high potential. However if the dome is negatively charged, shouldn't it be very low potential?


Potential is defined as the epe per test charge at a certain point.

And when we don't know the distance between a test charge and the dome, what is meant by "potential of the dome."

更新 2:

Is it referring to the surface potential of the dome?

2 個解答

  • 天同
    Lv 7
    4 年前

    The word "high" here carries a relative concept. It means a "high potential difference relative to ground". Should the dome carry large amount of -ve charges, the potential difference of it would still be high in respect to earth potential."

    If an object carries charges, it will acquire a certain potential from the charges. At the same time, the charged object will also raise (or lower, if the charges are -ve) the potential of the surrounding space.

    That said, charges accumulated on the dome of a van de Graff generator cause the dome to acquire a certain potential.

    In terms of the definition of potential, the "potential of the charged dome (assume the charges are +ve)" is the work done required to bring a (+ve) unit test charge from infinity to reach the dome.

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  • aston
    Lv 5
    3 年前

    yes, you correct. but it is normal positively charged

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