A coil of 0.01 henry inductance and 1 ohm resistance is connected to 200 volt, 50 Hz ac supply. Find the impedance of the circuit and time lag between max. alternating voltage and current.

Answer

A

Explanation

Given, inductance L=0.01 H
resistance R = `1Omega`, voltage(V) = 200V
and frequency (f)= 50Hz.
Impedance of the circuit, `Z = sqrt(R^(2) + X_(L)^(2))` = `sqrt(R^(2) + (2pifL)^(2))`
`=sqrt(1^(2)+ (2 xx 3.14 xx 50 xx 0.01)^(2))`
`Z= sqrt(10.86) = 3.3 Omega`
`tanphi = (omegaL)/(R) = (2pifL)/(R) = (2 xx 3.14 xx 50 xx 0.01)/(1) = 3.14`
`phi = tan^(-1)(3.14)=72^(@)`
Phase difference `phi=(72 xx pi)/(180)` rad.
Time lag between alternating voltage and current
`Deltat = phi/(omega) = (72pi)/(180 xx 2phi xx 50) = 1/250`s