Phy electric field & potential

fgsfd

2015-05-17 5:34 am

35.A hollow conducting sphere is carrying postive charges.
The radius from centre to the inner surface of the sphere is b.
The radius from centre to the outer surface of the sphere is a.

How does the potential V vary with the radius starting from the centre?And why ?
(i.e from radius 0 to b and then to a)

回答 (1)

天同

2015-05-17 7:58 am

✔ 最佳答案

Because the sphere is a "conducting sphere", all charges reside on the outer surface of the sphere. There is no charge on the inner surface.

Suppose these charges give the sphere a potential Vo, say. Then,
from 0 < r < b, potential V = Vo
from b = r = a, potential V = Vo
from r > a, potential V falls inversely as the distance from the centre of the sphere.

Note that electric filed only exists outside the sphere. There is no electric field inside hollow cavity of the sphere.

2015-05-17 12:59:06 補充：
Just a clarificaton, "b = r = a" indicates that r is between b and a and includes both points.

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