Two point charges `+3 muC` and `+8muC` repel each other with a force of `40 N`. If a charge of `-5 muC` is added to each of them, then the force between them will become

Answer

A

Explanation

Redistribution of charges tekkes place.
Charge, `q_(1)=3muC` and Charge, `q_(2)=8muC`
When thrid charge `q_(3)=-5muC` is added to each, then new charge on `q_(1) and q_(2)` will be
`q'_(1)=3-5=-2muC`
`and" "q'_(2)=8-5=3muC`
Now,
Case I`" "40=(1)/(4pi epsilon_(0)).(3xx8)/(r^(2))`
Case II`" "F=(1)/(4pi epsilon_(0))xx((-2xx3))/(r^(2))`
`therefore" "(F)/(40)=(-2xx3)/(3xx8) rArr F=-10N`