Assuming both the voltage sources are in phase, the value of R for which maximum power is transferred from circuit A to circuit B is

If $$V_A-V_B=\;6\;V$$, then $$V_C-V_D$$ is

A two phase load draws the following phase currents: $$i_1\left(t\right)=I_m\sin\left(\omega t-\phi_1\right)$$, $$i_2\left(t\right)=I_m\cos\left(\omega t-\phi_2\right)$$. These currents are balanced if $$\phi_1$$ is equal to

In the circuit shown, the three voltmeter readings are V₁ = 220V, V₂ = 122V , V₃ = 136V. The power factor of the load is