Two passive two-port networks are connected in cascade as shown in figure. A voltage source is connected at port 1. $$\begin{array}{l}Given:\\V_1=A_1V_2+B_1I_2\\I_1=C_1V_2+D_1I_2\\V_2=A_2V_3+B_2I_3\\I_2=C_2V_3+D_2I_3\end{array}$$

$$A_1,\;B_1,\;C_1,\;D_1,\;A_2,\;B_2,\;C_2,\;and\;D_2$$ are the generalized circuit constants. If the Thevenin equivalent circuit at port 3 consists of a voltage source V_T and impedance Z_T connected in series, then

The power supplied by the 25 V source in the figure shown below is ________W.

The following measurements are obtained on a single phase load: $$V = 220 V$$ $$ \pm $$$$1$$%. $${\rm I}$$$$= 5.0$$ $$A$$ $$ \pm \,1$$% and $$W=555$$ $$W$$ $$ \pm \,2$$%. If the power factor is calculated using these measurements, the worst case error in the calculated power factor in percent is _________. (Give answer up to one decimal place.)

The load shown in the figure is supplied by a $$400$$ $$V$$ (line-to-line) $$3$$-phase source ($$RYB$$ sequence). The load is balanced and inductive, drawing $$3464$$ $$VA.$$ When the switch $$S$$ is in position $$N$$, the three watt-meters $${W_1},\,{W_2}$$ and $${W_3}$$ read $$577.35$$ $$W$$ each. If the switch is moved to position $$Y,$$ the readings of the watt-meters in watts will be: