Electrostatic Potential and Capacitance Mind Map

Electric potential at a point is the work done per unit positive test charge in bringing it from infinity to that point without changing its kinetic energy.

In numericals, first decide the sign of each source charge, then substitute in V = kq/r. Do not put the test charge into the formula for potential due to a source charge.

The potential at a point due to a system of charges is the algebraic sum of potentials due to individual charges. For an electric dipole, potential depends on distance from the dipole and the angle with its axis.

For dipole potential, check whether the point is axial, equatorial, or at a general angle before applying the formula.

An equipotential surface is a surface on which every point has the same electric potential.

In diagram questions, mention both facts: work done along an equipotential surface is zero, and electric field is normal to the surface.

Electrostatic potential energy of a system of charges is the work required to assemble the charges from infinity to their given positions without changing their kinetic energy.

For three charges, write the three pair terms clearly: q1q2/r12, q1q3/r13, and q2q3/r23. This prevents double counting.

A capacitor is a device that stores equal and opposite charges on two conductors separated by an insulating medium. Capacitance is the charge stored per unit potential difference between the conductors.

For capacitor combinations, first identify whether the same potential difference is across capacitors or the same charge is on them. Same V usually indicates parallel; same Q usually indicates series.

Energy stored in a charged capacitor is the work done in charging it and is stored in the electric field between its plates.

Before choosing the energy formula, check whether Q, V, or C is given. In dielectric questions, check whether the battery is connected or disconnected.