$$ \text { The input impedance, } Z_{\text {in }}(s) \text {, for the network shown is } $$

Two single-core power cables have total conductor resistances of $0.7 \Omega$ and $0.5 \Omega$ respectively and their insulation resistances (between core and sheath) are $600 \mathrm{M} \Omega$ and $900 \mathrm{M} \Omega$ respectively. When the two cables are joined in series, the ratio of insulation resistance to conductor resistance is $\_\_\_\_$ $\times 10^6$

In the given circuit, the value of capacitor $C$ that makes current $I=0$ is $\_\_\_\_$ $\mu \mathrm{F}$.

A three-phase balanced voltage is applied to the load shown. The phase sequence is RYB. The ratio $\left|\frac{I_B}{I_R}\right|$ is $\_\_\_\_$ .