When the two-wattmeter method is used to measure power in a balanced three-phase circuit, if one wattmeter reads zero and the other reads a positive maximum value, then what is the power factor of the circuit?

When two alternators are synchronized using a moving-iron synchroscope, on what does the speed and direction of rotation of the synchroscope pointer depend?

Which of the following instruments is primarily used to measure high insulation resistance?