Energy Stored In Capacitor — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Energy Stored in a Capacitor This formula applies to the energy stored in an ideal capacitor when a potential difference (voltage) is applied across its plates. The energy stored (U) is equal to the work done (W) by the external source to charge the capacitor. The work done is calculated by integrating the potential difference (V) with respect to the accumulated charge (Q): W = V dQ. Using the relationship Q = CV, the integral becomes: W = V d(CV) = 1 2 CV 2. The energy stored can also be expressed as U = Q 2 2C or U = 1 2 QV, demonstrating the equivalence of the forms. Capacitance C must be positive. Voltage V must be measured relative to the potential difference across the plates. Confusing the stored energy (U) with the potential difference (V) or the charge (Q). Forgetting the factor of 1/2 in the energy equations. Assuming the energy stored depends on the physical size of the capacitor plates rather than the capacitance C.