Here is ac circuits important formulas which may come to your rescue while solving numericals

USEFUL AC FORMULAS
PERIOD TIME (t)

FREQUENCY (f)

AVERAGE VOLTAGE OR CURRENT

EFFECTIVE VALUE OF VOLTAGE OR CURRENT

MAXIMUM VOLTAGE OR CURRENT

OHM'S LAW OF AC CIRCUIT CONTAINING ONLY RESISTANCE

L/R TIME CONSTANT (TC)


MUTUAL INDUCTANCE (M)

TOTAL INDUCTANCE (L_T) Series without magnetic coupling

TOTAL INDUCTANCE (L_T) PARALLEL (No magnetic coupling)

CAPACITANCE (C)



RC TIME CONSTANT (t)


TOTAL CAPACITANCE (C_T) SERIES


TOTAL CAPACITANCE (C_T) PARALLEL

INDUCTIVE REACTANCE (X_L)

CAPACITIVE REACTANCE (X_C)

IMPEDANCE (Z)



OHM'S LAW FOR REACTIVE CIRCUITS

OHM'S LAW FOR CIRCUITS CONTAINING RESISTANCE AND REACTANCE


REACTIVE POWER

APPARENT POWER

POWER FACTOR (PF)


VOLTAGE ACROSS THE SECONDARY (E_s)

VOLTAGE ACROSS THE PRIMARY (E_p)

CURRENT ACROSS THE SECONDARY (I_s)


CURRENT ACROSS THE PRIMARY (I_p)

TRANSFORMER EFFICIENCY