Two copper balls, each weighing `10 g` are kept in air `10 cm` apart. If one electron from every `10^(6)` atoms in trandferred from one ball to the other, the coulomb force between them is (atomic weight of copper is `63.5`)

Options

A. `2.0xx10^(10)N`
B. `2.0xx10^(4)N`
C. `2.0xx10^(8)N`
D. `2.0xx10^(6)N`

Answer

C

Explanation

Number of electrons n
`(6xx10^(23))/63.5 xx 10 xx 1/(10^(6))=(6xx10^(18))/63.5`
`q=(6xx10^(18)xx1.6xx10^(-19))/63.5C`
or `q=1.5xx10^(-2)C`
`F=(9xx10^(9)xx1.5xx10^(-2)xx1.5xx10^(-2))/((10/100))N`
`=2.0.10^(8)N`