one voltmeter and one ammeter
one voltmeter, one ammeter and one wattmeter
one voltmeter, one ammeter and one energy meter
any of the above
Answer is Right!
Answer is Wrong!
The correct answer is: A. one voltmeter and one ammeter.
To calculate the power factor of a single phase load, you need to know the voltage and current. You can measure these with a voltmeter and an ammeter. The power factor is then calculated as:
Power factor = cos(phi) = V/I
where V is the voltage and I is the current.
Option B is incorrect because you do not need a wattmeter to calculate the power factor. Option C is incorrect because you do not need an energy meter to calculate the power factor. Option D is incorrect because only option A is correct.