Question

How many electrons must be removed from a neutral, isolated conducting sphere to give it a positive charge of 8.0 x 10 8 C? [Q=ne]

Answer 1

Answer: the ball will have a charge of 8x10^8C when we remove 5x10^27 electrons.

Explanation:

If the sphere is neutral, then the charge of the sphere is 0C

Now, when we remove an electron (-1.6*10^-19 C) we are subtracting a negative number, so the new charge of the sphere is: 1.6*10^-19 C

Now, for N removed electrons, the charge of the sphere is:

N*1.6*10^-19 C

We want to find the number N when:

N*1.6*10^-19 C = 8.0x 10^8 C

N = (8.0/1.6)x10^(8 + 19) = 5x10^27 electrons.