A current through 1 $$\Omega$$ resistance in the following circuit is

In a meter bridge experiment, the balance point is obtained at length $$\ell_1 \mathrm{~cm}$$ from left end when resistances in the left gap and right gap are $$5 \Omega$$ and $$R \Omega$$ respectively. When the resistance $$R$$ is shunted with equal resistance, the new balance point is at $$1.6 \ell_1$$. The resitance $$R$$ in ohm is

Two wires '$$\mathrm{A}$$' and '$$\mathrm{B}$$' of equal length are connected in left and right gap respectively of meter bridge, null point is obtained at $$40 \mathrm{~cm}$$, from the left end. Diameters of the wires '$$A$$' and '$$B$$' are in the ratio $$3: 1$$ respectively, the ratio of specific resistance of 'A' to that of 'B' is

A galvanometer has resistance '$$\mathrm{G}$$' $$\Omega$$ and '$$\mathrm{I}_{\mathrm{g}}$$' is current flowing through it which produces full scale deflection. '$$\mathrm{S}_1$$' is the value of shunt which converts it into an ammeter of range 0 to '$$3 \mathrm{I}$$' and '$$\mathrm{S}_2$$' is the shunt value which converts it into an ammeter of range 0 to '$$4 \mathrm{I}$$', the ratio $$\mathrm{S}_2: \mathrm{S}_1$$ is