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?

Explanation

For an LR circuit, if `V=V_(0)sin omega t`
`I=(V_(0))/(sqrt(R^(2)+omega^(2)L^(2))) sin (omega t -phi)`, where `tan phi=(omega L//R)`.
(a) `I_(0)=1.82A`
(b) V is maximum at t = 0, I is maximum at `t=(phi//omega)`.
Now, `tan phi=(2pi vL)/(R ) = 1.571 or phi ~~57.5^(@)`
Therefore, time lag `=(57.5pi)/(180)xx(1)/(2pi xx 50)=3.2 ms`