Two identical balls each have a mass of `10 g`. What charges should these balls be given so that their interaction equalizes the force of universal gravitation acting between them? The radii of the balls may be ignored in comparison to distance between them.

Options

A. `6.34xx10^(-11)C`
B. `8.57xx10^(-11)C`
C. `6.34xx10^(-13)C`
D. `8.57xx10^(-13)C`

Answer

d

Explanation

If `q` is charge given to each ball, then
`1/(4piepsilon_(0))*(qxxq)/(r^(2))=G(mxxm)/(r^(2))`
or `q=sqrt(4piepsilon_(0)G)xxm`
Setting `G= 6.6xx10^(-11) Nm^(2) kg^(-2)` and
`m=10 g=10xx10^(-3)kg`, we get
`q=8.57xx10^(-13)C`