Consider the circuit shown in the figure. The value of current 'I' is
An ammeter of resistance $$20 \Omega$$ gives full scale deflection, when $$1 \mathrm{~mA}$$ current flows through it. What is the maximum current that can be measured by connecting 4 resistors each of $$16 \Omega$$ in parallel with the ammeter?
Two wires $$A$$ and $$B$$ of equal lengths are connected in left and right gap of a meter bridge, null point is obtained at $$40 \mathrm{~cm}$$ from left end. Diameters of the wire $$A$$ and $$B$$ are in that ratio $$3: 1$$. The ratio of specific resistance of $$A$$ to the of $$B$$ is
A potentiometer wire is $$4 \mathrm{~m}$$ long and potential difference of $$3 \mathrm{~V}$$ is maintained between the ends. The emf of the cell, which balances against a length of $$100 \mathrm{~cm}$$ of the potentiometer wire is