Alternating Current

Chapter-7|Alternating Current | NCERT 12th Physics:

Alternating Current:

If the direction of current changes alternatively and its magnitude changes continuously with respect to time is called alternating current.

Alternating current changes continuously between zero and maximum value and flows in one direction in the first half cycle and in the opposite direction in the next half cycle.

The instantaneous value of AC


Where, I = Current at any instant t.

             I₀= Maximum/Peak value of AC

             f= Frequency and ω= Angular Frequency

Alternating EMF or Voltage:

Alternating voltage can be defined as the voltage whose magnitude and direction changes with time and attains the same magnitude and direction after a definite time interval.

The instantaneous value of alternating EMF

                             E= E₀Sinωt

Where,  E= Voltage at any Instant t

E₀= Maximum value of alternating voltage

ω= Angular Frequency.


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