In figure below, the point charge `Q_(1)` causes an electric potential of `60 V` and an electric field strength of `30 Vm^(-1)` at `P`. and the point charge `Q_(2)` separately causes a potential of `120 V` and a field strength of `40 Vm^(-1)` at `P`.
Which one the following gives possible value of potential and field strength at `P` due to joint action of `Q_(1)` and `Q_(2)` ?

Options

A. Potential`//V`, Field`//Vm^(-1)`
`180`, `70`
B. Potential`//V`, Field`//Vm^(-1)`
180, 50
C. Potential `//V`, Field `//Vm^(-1)`
135, 50
D. Potential `//V`, Field `//Vm^(-1)`
60, 10

Answer

B

Explanation

The electric potential at `P` due to charges `Q_(1)` and `Q_(2)` is the algebraic sum of the potentials due to individual charges at point `P`. Hence, the electric potential at is now `(120 + 60)` or `180 V`.
On the other hand, the electric field strength at `P` due to strengths due to individual charges at point `P`. a possible value of the resultant field strength is `50Vm^(-1)` as shown.