Question

Question #6f365

Answer 1

The answer is `25" N"`

Method
Coulomb's law: `abs(F)=K(q_1q_2)/r^2`

where
`F` is magnitude of the electrostatic force
`K` is a costant `K=1/(4piepsilon_0)`
`q_1` and `q_2` are the magnitudes of the charges
`r` is the distance separating the charges
`=>F` `alpha` `1/r^2`

Hence,

`F_1(r_1)^2=F_2(r_2)^2`

`F_1=1.0 "N , " r_1=5"cm"=5xx10^-2"m"`
`r_2=1.0"cm"=10^-2"m"`

So, we are looking for `F_2` , right?

`=>F_2=(F_1(r_1)^2)/(r_2)^2=(1xx(5xx10^-2)^2)/(10^-2)^2=25`