Question

 An alternating emf is applied to a series combination of an inductor and a resistor (R = 100 Ω ). If the impedance of the circuit is `100 sqrt2  Ω`, what is the phase difference between the emf and the current?

Answer 1

Data: R = 100 Ω, Z = `100 sqrt2 Ω`

cos Φ = `R/Z`

= `100/(100sqrt2)`

= `1/sqrt2`

∴ `Φ = cos^-1 (1/sqrt2)`

= π/4 rad

= 45°

This is the phase difference between the emf and the current.