# Alternating Current formulae for NEET

Alternating current is a current that changes its magnitude and polarity at regular interval of time. If the current maintains its direction constant it is called direct current.

AC voltage, v = V0sinÏ‰t

AC current, i = I0sinÏ‰t

Capacitive ReactanceÂ V0/I0 = 1/Ï‰C = Xc

RMS voltage, Vrms = V0/âˆš2

RMS current, Irms = I0/âˆš2

Inductive ReactanceÂ Â V0/I0 =Â Ï‰L = XL

Phase angle of an RLC series circuitÂ Î¦ = tan-1 (XL – XC)/R

AC version of Ohm’s law,Â I0 = V0/Z

RLC series circuit Impedance ,Â

$$\begin{array}{l}Z= \sqrt{R^{2}+(X_{L}-X_{C})^{2}}\end{array}$$

Average power associated with circuit element, Pavc = (1/2)I0V0cosÂ Î¦

Resonant angular frequency of the circuit,Â Ï‰0 =Â âˆš1/LC

Root Mean Square:Â The Root mean square of a function from T1 to T2 is given by

Power Consumed or Supplied in AC circuit

The average power consumed in a cycle

Purely Resistive Circuit:Â In a purely resistive circuit, the power is dissipated by the resistance and phase of both voltage and current remains the same.

P = VrmsIrms cosÎ¦ =Â Vrms2/R

Pure Inductive Circuit:Â In a purely inductive circuit current lags the voltage by 900

i = imÂ sin(Ï‰t- Ï€/2)

Purely Conductive Circuit:Â In a purely inductive circuit, the current flowing through the capacitor leads the voltage by 900.

I = {Vm/(1/Ï‰C)}cosÏ‰t

I = (Vm/Xc)cosÏ‰t

I = ImcosÏ‰t

I =Â Imsin(Ï‰t +Â Ï€/2)

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Electric Current and Electrical Networks | Ohm’s Law in Scalar form | NEET 2021/2022/2023 | Physics

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