Question

please solve this immideately

Answer 1

Ok so for minimum potential energy charges having large magnitude should be at the largest distance possible so

2q and 8q should be 6cm apart

and let q be x cm distance apart from 2q and (6-x)cm from 8q

Then

potential energy

is Kq(2q)/x+Kq(8q)/6-x

Now to have min. potential dU/dx be zero

Then

we will get x=2cm