In the given circuit, for voltage V_y to be zero, the value of β should be ______. (Round off to 2 decimal places).

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 $\_\_\_\_$ $\mu \mathrm{F}$.

Currents through ammeters A₂ and A₃ in the figure are 1∠10° and 1∠70°, respectively. The reading of the ammeter A₁ (rounded off to 3 decimal places) is _____ A.