The equivalent inductance seen at terminals $$A-B$$ in Fig. is .................... $$H.$$

Using Thevenin equivalent circuit, determine the $$rms$$ value of the voltage across the $$100$$ $$ohm$$ resistor after the switch is closed in the $$3$$ $$-$$ phase circuit shown in Figure.

The time constant of the network shown in Fig. is

Resistances in the circuit of fig. are of R $$\Omega$$ each. The switch is initially open. What happens to the lamp's intensity when the switch is closed?