Question

A coil of inductance `0.50H` and resistance `100 Omega` is connected to a `240V`, `50Hz` ac supply. What are the maximum current in the coil and the time lag between voltage maximum and current maximum?

Answer 1

Given, Inductance L = 0.50 H
Resistance `R = 100 Omega`
`V_("rms")=240V, f=50Hz`
Using the formula of time lag,
`t=(phi)/(omega)`
`tan phi = (X_(L))/(omega)=(omega L)/(R )=(2pi fL)/(R )= (2xx3.14xx50xx0.50)/(100)`
`phi = tan^(-1)(1.571)=57.5`
`phi=(57.5)/(180)pi` rod
Time lag `t=(phi)/(omega)=(57.5pi)/(180xx2pi f)`
`= (57.5)/(180xx2xx50)`
`= 3.19xx10^(-3)S`
Thus, the time lag between the voltage maximum and the current maximum is `3.19xx10^(-3)S`.