Viewed from the terminals $$A, B$$ the following circuit shown in Figure can be reduced to an equivalent circuit of a single voltage source in series with a single resistor with the following parameters:

The effective inductance of the circuit across the terminals $$A,B$$ in the Figure shown below is

In the circuit shown in Figure, it is desired to have a constant direct current $$i(t)$$ through the ideal inductor $$L.$$ The nature of the voltage source $$v(t)$$ must be

A d.c. voltmeter has a sensitivity of $$1000$$$$\Omega /volt.$$ When it measures half full scale in $$100$$ $$V$$ range, the current through the voltmeter is