AC circuit for circuit with only resistor:
Let us take an AC circuit has only pure ohmic resistance ‘R’ & the applied voltage e = Em sin ωt.
Now, the alternating current, i = e/R = Em sin ωt/R
The value of the alternating current ‘i’ is maxm. When sin ωt = 1
So, we can write = Im = Em / R
Therefore, the alternating current and alternating voltage in a pure resistance circuit are in phase and the angular difference between current & voltage vector is zero.