A moving coil galvanometer is converted into an ammeter, reading upto $$0.04 \mathrm{~A}$$ by connecting a shunt of resistance '$$3 \mathrm{r}$$' across it and then into an ammeter reading upto $$0.8 \mathrm{~A}$$, when a shunt of resistance '$$r$$' is connected across it. What is the maximum current which can be sent through this galvanometer if no shunt is used?

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