Physics · Electrostatic Potential And Capacitance · NEET
No. Electric potential is a SCALAR. For a system of charges you add the individual potentials as plain numbers, keeping each charge's + or − sign: V = kq₁/r₁ + kq₂/r₂ + ... There are no components, no arrows and no angles between them. This is why potential problems are usually easier than field problems for the same charge arrangement.
Use the charge with its own sign inside V = kq/r. For a −2 μC charge you write V = k×(−2×10⁻⁶)/r, which gives a negative potential. Then add it to the other terms. The distance r is always taken as a positive number (a magnitude); only the charge carries the sign.
Every corner charge is the same distance from the centre, r = (side)/√2 (half the diagonal). So V_centre = k(q₁+q₂+q₃+q₄)/r. Just add the corner charges with signs, then divide by that one distance. If the four charges add to zero, the potential at the centre is zero even though the field there may not be.
Yes, and NEET loves this. Field E is a vector, potential V is a scalar. Two equal positive charges: at the midpoint the two field vectors cancel (E = 0) but the two potentials ADD (V ≠ 0). Field zero does not force potential zero, and potential zero does not force field zero. Treat them separately.
Always the straight-line (shortest) distance from each charge to the point where you want the potential. Potential depends only on that direct distance r, not on any path you imagine walking. This follows from the electrostatic force being conservative.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
V = (1/4πε₀) Σ qᵢ/rᵢ = k(q₁/r₁ + q₂/r₂ + ... + qₙ/rₙ), where k = 9×10⁹ N·m²/C², each qᵢ is taken with its own sign, and rᵢ is the straight-line distance of charge qᵢ from the point.
Because of the superposition principle and because potential is a scalar built from conservative forces. The work done per unit charge from each source adds independently, so the total potential is the algebraic sum of the individual potentials.
Yes. If the signed terms cancel, for example equal + and − charges equally distant from the point, the net potential is zero at that point. This is common at the midpoint of a dipole's perpendicular bisector or the centre of a symmetric charge set that sums to zero.
No. Potential has magnitude and sign only, no direction. Only the electric field of the system has direction. This is the single most important idea to separate the two in NEET problems.
The same as any potential: volt (V), where 1 V = 1 joule per coulomb (J/C). Each kq/r term already comes out in volts, and their sum is in volts.
