Electric Current Instantaneous I Dq Dt — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Electric Current (Instantaneous): I = dq / dt Applicable for determining instantaneous current when the flow of charge varies with time. Fundamental definition used in transient analysis (RC, RL circuits) and AC circuits. Define average current as the ratio of total charge to time interval: I avg = Δq / Δt. Apply the limit as the time interval Δt approaches zero to find the instantaneous rate of change. Result implies I = lim(Δt→0) Δq/Δt = dq/dt. dt must approach zero for true instantaneous value. Charge must be continuous. Confusing instantaneous current with average current (I = q/t) which is only valid for steady flows. Believing current is a vector quantity because it has direction (it is a scalar quantity obeying Kirchhoff's laws, not vector addition).