In the two port network shown in the figure below, z₁₂ and z₂₁ are, respectively

A two-port network is represented by ABCD parameters given by $$\left[ {\matrix{ {{V_1}} \cr {{I_1}} \cr } } \right] = \,\left[ {\matrix{ A & B \cr C & D \cr } } \right]\,\left[ {\matrix{ {{V_2}} \cr { - \,{I_2}} \cr } } \right]$$

If port-2 is terminated by $${R_L}$$, the input impedance seen at port-1 is given by

If R₁ = R₂ = R₄ = R and R₃ = 1.1R in the bridge circuit shown in figure, then the reading in the ideal voltmeter connected between a and b is

The h parameters of the circuit shown in Fig. are