Question

Question #20de5

Answer 1

`r=0.3927 m`

`r=39.27 cm` (approx)

Explanation:

The force between two point charges is `->`

`F=1/(4pi epsilon_0) xx (Q_1*Q_2)/r^2`

where `r` is the distance between the two charges.

Here we know

`F=175 N`

`Q_1=60 muC` which is `60 xx 10^(-6) C`

`Q_2=50 muC` which is `50 xx 10^(-6) C`

`1/(4pi epsilon_0) = 9 xx 10^9 Nm^2/C^2`

So,

`175=(9 xx 10^9 xx 60 xx 10^(-6) xx 50 xx 10^(-6))/r^2`

`175=(9 xx 10^9 xx 60 xx 50)/(10^6 xx 10^6 xx r^2)`

`r^2=(9 xx 6 xx 5 )/(10 xx 175)`

`r=sqrt((270/1750)) m`

`r=sqrt(0.154285) m`

`r=0.3927 m`

`r=39.27 cm` (approx)