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 ............. $V$.

The temperature coefficient of resistance of tungsten is $4.5 \times 10^{-3} \, ^{\circ}C^{-1}$ and that of germanium is $-5 \times 10^{-2} \, ^{\circ}C^{-1}$. $A$ tungsten wire of resistance $100 \, \Omega$ is connected in series with a germanium wire of resistance $R$. The value of $R$ for which the resistance of the combination does not change with temperature is .......... $\Omega$.

Two bulbs of $500\, W$ and $200\, W$ are manufactured to operate on a $220\, V$ line. What is the ratio of heat produced in the $500\, W$ bulb to the $200\, W$ bulb when they are connected in parallel,and when they are connected in series?

The two ends of a uniform conductor are joined to a cell of $e.m.f.$ $E$ and some internal resistance. Starting from the midpoint $P$ of the conductor,we move in the direction of current and return to $P$. The potential $V$ at every point on the path is plotted against the distance covered $(x)$. Which of the following graphs best represents the resulting curve?

In a thermocouple,the temperature that does not depend on the temperature of the cold junction is called

$A$ cell of emf $\varepsilon$ and internal resistance $r$ is connected across a variable load resistance $R$. The graph drawn between its terminal voltage $V$ and resistance $R$ is