In a copper voltameter,the mass deposited in $30\, \text{s}$ is $m\, \text{g}$. If the current-time graph is as shown in the figure,the Electrochemical Equivalent $(ECE)$ of copper is:

When a current of $2 \ A$ flows through a conductor,$80 \ J$ of heat is produced in $10 \ s$. The resistance of the conductor is ........... $\Omega$.

The equivalent resistance between the points $P$ and $Q$ of the circuit given is

The resistance between the terminal points $A$ and $B$ of the given infinitely long circuit will be

The total current supplied to the given circuit by the battery is . . . . . . . (in $A$)

The thermo $e.m.f.$ of a thermocouple is $25\,\mu V/^{\circ}C$ at room temperature. $A$ galvanometer of $40\,\Omega$ resistance, capable of detecting current as low as $10^{-5}\,A$, is connected with the thermocouple. The smallest temperature difference that can be detected by this system is ................ $^{\circ}C$.