Two charges `+4e` and `+e` are at a distance `x` apart. At what distance,a charge `q` must be placed from charge `+e` so that is in equilibrium

Options

A. `x//2`
B. `2x//3`
C. `x//3`
D. `x//4`

Answer

D

Explanation

For equilibrium of `q`
`|F_(1)|=|F_(2)|`
`(BMS_OBJ_XII_C01_E01_066_S01.png" width="80%">
Which gives `x_(2)= (x)/(sqrt(Q_(1)/(Q_(2)))+1)=(x)/(sqrt(9e)/(e)+1)=(x)/(4)`