When is the error under testing of energy meter directly obtained?

The meter under test and the rotating substandard meter constants are zero.

The meter under test and the rotating substandard meter constants are same.

The meter under test and the rotating substandard meter constants are 1.

The meter under test and the rotating substandard meter constants are different.

Solution

Correct option is B

When performing error testing of an energy meter, the error is directly obtained when the meter under test and the rotating substandard meter have the same constants. This ensures that the comparison between the two meters will give a direct measurement of the error.