66) Efficiency of transformers is determined by knowing its input and output power. Unit of power used for this purpose is kVA/kW. What is the unit used for input and output when calculating the all day efficiency ?

67) The transformer used in conjunction with voltmeter is called a potential transformer. The standard rating of secondary of potential transformer is :

68) Secondary of a current transformer will have :

69) If the current rating of the installation is high, a current transformer is used in the energy meter circuit. If a current transformer of 100A/5A is connected with an energy meter, the multiplying factor for the recorded energy is

70) In constant voltage transformer at certain induced secondary voltage, the impedance of secondary winding will become equal to impedance of the capcitor across it. What is this condition of circuit known as ?