Two charges `4muC and 1 muC` are placed at distance of 10 cm. Where should a third charge be placed between them so that it does not experience any force .

Explanation

`Q_(1)=4muC = 4xx10^(-6)C`
`Q_(2) =1muC = 1xx10^(-6)C`
`d=10cm`
Let the third charge Q be placed at a distance at a distance of x from `Q_(1)` then x = ?
`(Q_(1))/(x^(2)) =(Q_(2))/((10-x)^(2))`
`(4xx10^(-6))/(x^(2)) =(1xx10^(-6))/((10-x)^(2)), (2)/(x)=(1)/(10-x)`
`x=(20)/(3)cm` from `4muC`.