A $$100$$ $$\mu A$$ ammeter has an internal resistance of $$100\,\Omega $$. For extending its range to measure $$500$$ $$\mu A$$, the shunt required is of resistance (in $$\Omega $$)

The minimum number of wattmeter(s) required to measure 3 $$-$$ phase, 3 $$-$$ wire balanced or unbalanced power is

In case of an armature controlled separately excited dc motor drive with closed loop speed control, an inner current loop is useful because it

An electric motor with 'constant output power' will have a torque speed characteristic in the form of a