Two small conducting sphere of equal radius have charges `+1Cand-2C` respectively and placed at a distance d from each other experience force `F_(1)`. If they are brought in contact and separated to the same distance, they experience force `F_(2)`. The ratio of `F_(1)` to `F_(2)` is .....................

Options

A. `-8:1`
B. `1:2`
C. `1:8`
D. `-2:1`

Answer

A

Explanation

`F_(1)=k((+1)(-2))/(r^(2))=-(2k)/(r^(2)),F_(2)=k((-(1)/(2))(-(1)/(2)))/(r^(2))=(1)/(4)(k)/(r^(2)),(F_(1))/(F_(2))=(-8)/(1)`