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8. Coil rotating in uniform magnetic induction .

where i_{0 = }

e_{0}

peak value of current.

R

9. rms value of alternating current / e.m.f.

i_{rms}_{ = }

i_{0}

= 0.707 i_{0}

where

i_{rms} = root mean square (rms) value of current

i_{0} = peak value of current.

e_{rms}_{ = }

= 0.707 e_{0}

e_{rms} = root mean square (rms) value of e.m.f

e_{0} = peak value of current.

10. In case of a purely resistive circuit to which an a.c. voltage is applied,

average power P = e_{rms} × i_{rms}_{ }

=

´

e_{0} i_{0}

2

11. Inductive reactance X_{L} = wL = 2p f L

f = frequency of the applied a.c. voltage

L = inductance.

12. Capacitive reactance

X_{C} =

1

wc

2pfc

C = Capacitance

13. Impedance (Z) when L and R are connected in series:

When an inductance L and a resistance R are connected in series, the impedance Z is given by Z =

14. Impedance (Z) when C and R are connected in series:

When a capacitor of capacitance C and a resistance R are connected in series, the impedance Z is given by Z =

15. In a L-C-R series circuit

tan f =

X_{L}- X_{c}

where f = the angle by which e.m.f. leads the current.

Z = where Z = impedance of the circuit resonant frequency f =

2p

L = inductance

C = capacitance

16. Parallel resonant circuit

The resonant frequency f_{r} =