The $$Z$$ matrix of a $$2$$ $$-$$ port network is given by $$\left[ {\matrix{ {0.9} & {0.2} \cr {0.2} & {0.6} \cr } } \right].$$ The element $${Y_{22}}$$ vof the corresponding $$Y$$ matrix of the same network is given by

A galvanometer with a full scale current of $$10$$ $$mA$$ has a resistance of $$1000$$$$\Omega $$. The multiplying power (the ratio of measured current to galvanometer current) of a $$100$$$$\Omega $$ shunt with this galvanometer is

A moving coil of a meter has $$100$$ turns, and a length and depth of $$10$$ $$mm$$ and $$20$$ $$mm$$ respectively. It is positioned in a uniform radial flux density of $$200$$ $$mT.$$ The coil carries a current of $$50$$ $$mA.$$ The torque on the coil is

A moving iron ammeter produces a full scale torque of $$240$$ $$\,\mu Nm$$ with a deflection of $${120^ \circ }$$ at a current of $$10$$ $$A$$. The rate of change of self inductance $$\left( {\mu H/radian} \right)$$ of the instrument at full scale is