A $$3$$ - $$\phi $$ load operates with balanced voltages applied to its terminals, and draws balanced currents. The potential coil of a moving coil wattmeter is connected from $$R$$ to $$Y$$ terminals of the load. The current coil of the meter is connected in series with phase $$B.$$ by appropriate derivation, show that the quantity indicated by this wattmeter is proportional to the reactive power drawn by the load

A symmetrical $$400V,$$ $$3$$-$$\phi $$ supply is connected to the network shown in fig. The phase sequence is $$RYB.$$ Find the reading on the wattmeter

$${R_1} = 30\Omega ,\,\,{X_1} = 50\Omega ,\,\,$$ and $${X_2} = 40\Omega $$