Two point charges 20 C and -10 C are separated by a distance of 1 ~m in air. At what point on the line joining the two charges, the electric potential is zero.

Step-by-step solution

Let the two charges be q₁ = 20 10⁻⁶ C and q₂ = -10 10⁻⁶ C , separated by a distance d = 1 m . Let the point where the electric potential is zero be at a distance x from q₁ along the line joining the charges. The potential V at a point due to a charge q at distance r is given by V = kq r . The total potential at the point is the sum of potentials due to q₁ and q₂ . Setting the total potential to zero: k q₁ x + k q₂ d - x = 0 . Substituting the values: 20 10⁻⁶ x + -10 10⁻⁶ 1 - x = 0 . Dividing by 10⁻⁶ and simplifying