1)

The instantaneous voltage at three terminals marked X, Y and Z are given by VX= V0 sinωt.

VY=V0sin(ωt+2π3)and

VZ=V0sin(ωt+4π3)

 An ideal voltmeter is configured to read rms value of the potential difference between its terminals. It is connected between points X and Y and then between Y and Z . The reading (s) of the voltmeter will be


A) VrmsYZ=V012

B) VrmsXY=V032

C) independent of the choice of the two terminals

D) VrmsXY=V0

Answer:

Option B,C

Explanation:

VXY=V0sin(ωt+2π3)V0sinωt

  = V0sin(ωt+2π3)+V0sin(ωt+π)

   ϕ=π2π3=π3

   V0=2V0cos(π6)

            = 3V0

    VXY=3V0sin(ωt+ϕ)

(VXY)rms=(VYZ)rms=3V02