In the circuit shown in Fig. $$X$$ $$-$$ is an element which always absorbs power. During a particular operation, it sets up a current of $$1$$ $$amp$$ in the direction shown and absorbs a power $${P_{x}}.$$ It is possible that $$X$$ can absorb the same power $${P_x}$$ for another current $$i.$$ Then the value of this current is

The v - i characteristic as seen from the terminal pair (A,B) of the network of Fig.(1) is shown in Fig.(2). If an inductance of value 6 mH is connected across the terminal - pair (A,B), the time constant of the system will be

An advantage of a permanent magnet moving coil instrument is that it is

For a given frequency, the deflecting torque of an induction ammeter is directly proportional to