26) In which 3 phase system, the artificial neutral is required to measure the phase voltage?

27) What is the line voltage in 3 phase system if the phase voltage is 240V?

28) What is the power factor if one of the wattmeter gives negative reading in two wattmeter method of 3 phase power measurement?

29) What is the phase displacement between phases in a 3-phase circuit?

30) Which condition is called as resonance RLC circuit?