11.In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be

12.In a low power factor wattmeter the compensating coil is connected

13.For measuring current at high frequency we should use

14.Which of the following devices should be used for accurate measurement of low D.C. voltage ?

15.The adjustment of position of shading bands, in an energy meter is done to provide