Derive an expression for average power is an A.C. circuit containing resistor only.

Explanation

Average Power :-Average power in a.c. is defined as the product of apparent power and power factor.
Average Power = Apparent Power `xx` Power factor
Average power is also known as true power of an a.c. circuit.
Expression for Average Power of LCR series circuit.
Difference hetween true power and virtual power :
1. True power is measured in watts whereas virtual power is measured in volts-ampere.
2. True power is always less than or equal to virtual power.
3. True power can be measured by single instrument called wattmeter whereas to measure virtual power, we need a voltmeter and an ammeter.