#### JonathanCWalker

70. A hollow metal sphere 1.0m in diameter carries a charge of 4.0 "u" C. The electric field at a distance of 2.0m from the center of the sphere is most nearly
a. 9.0 x 10^3 N/C
b. 1.8 x 10^4 N/C
c. 2.4 x 10^4 N/C
d. 3.6 x 10^4 N/C
e. 1.4 x 10^5 N/C

The sphere has a radius of .5 m, so shouldn't the electric field be calculated from (1.5 m), which is the distance of the nearest excess charge to the point? Why must we calcuate taking r as 2.0 when there is no charge at the point in the center of the sphere?

Taking r to be 1.5, I get an answer of approx. 1.6 x 10^4 N/C

#### topsquark

Forum Staff
70. A hollow metal sphere 1.0m in diameter carries a charge of 4.0 "u" C. The electric field at a distance of 2.0m from the center of the sphere is most nearly
a. 9.0 x 10^3 N/C
b. 1.8 x 10^4 N/C
c. 2.4 x 10^4 N/C
d. 3.6 x 10^4 N/C
e. 1.4 x 10^5 N/C

The sphere has a radius of .5 m, so shouldn't the electric field be calculated from (1.5 m), which is the distance of the nearest excess charge to the point? Why must we calcuate taking r as 2.0 when there is no charge at the point in the center of the sphere?

Taking r to be 1.5, I get an answer of approx. 1.6 x 10^4 N/C

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