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

Explanation

We have `tan phi = ( X_(L ) - X_(C ))/( R )`
`:. tan phi = ( 2pi f L )/( R ) ( :.` Here, `X_(C ) = 0` ) ...(2)
`= ( 2 xx 3.14 xx 50 xx 0.5 ) /( 100)`
`:. tan phi = 1.57`
F= 50 Hz
`T = (1)/( 50) = 0.02 sec`
Phase difference ( rad ) Time
` 2pi ` 0.02
`1.57 xx (pi )/( 180)` (t )
` t = ( 0.02 xx 1.57 ) /( 2pi ) xx ( pi )/( 180)`
`= 3.2 xx 10^(-3) = 3.2 ms `