Correct Answer - Option 3 : EMMC
Concept:
Transfer instrument: An instrument which calibrated with a dc source and then used without modification to measure AC quantity. These instruments have the same accuracy for both dc and ac.
Explanation:
Precision type electrodynamometer (EMMC) is used in the standardization process of the potentiometer and hence It is a transfer instrument.
This instrument can be used as:
- Ammeter
- Voltmeter
- Wattmeter
- Reactive power meter (VAR meter)
- Power factor meter
- Frequency meter
