When $1\,g$ of hydrogen $(e.c.e. = 1.044 \times 10^{-8}\,kg/C)$ forms water,$34\,kcal$ of heat is liberated. The minimum voltage required to decompose water is ............. $V$.

$A$ $3\,^oC$ rise in temperature is observed in a conductor by passing a certain current. When the current is doubled,the rise in temperature will be ............. $^oC$.

The figure shows a network of four resistances and three batteries. The electrical power dissipated as heat in the circuit is .............. $W$.

Two wires with resistances $R$ and $2R$ are connected in parallel. The ratio of heat generated in $2R$ and $R$ is:

$A$ thermocouple develops $200\,\mu V$ between $0\,^{\circ}C$ and $100\,^{\circ}C$. If it develops $64\,\mu V$ and $76\,\mu V$ respectively between $(0\,^{\circ}C - 32\,^{\circ}C)$ and $(32\,^{\circ}C - 70\,^{\circ}C)$,then what will be the thermo-emf it develops between $70\,^{\circ}C$ and $100\,^{\circ}C$ in $\mu V$?

$A$ brass disc and a carbon disc of same radius are assembled alternatively to make a cylindrical conductor. The resistance of the cylinder is independent of the temperature. The ratio of thickness of the brass disc to that of the carbon disc is [$\alpha$ is temperature coefficient of resistance and neglect linear expansion].