The absolute potential at a distance of 20 m from a negative

The absolute potential at a distance of 2.0 m from a negative point charge is-100. V. What is the absolute potential 4.0 m away from the same point charge? A)-50. V B) -25. V C)-0.40 kV D)-020 kV E)-0.50 kV

Solution

since potential due to a point charge is given by

V=KQ/r

=>V₁/V₂ =r₂/r₁

=>V₂=V₁*(r₁/r₂) =-100*(2/4)

V₂=-50 V