The thermo emf of a hypothetical thermocouple varies with the temperature $\theta$ of the hot junction as $E = a\theta + b\theta^2$ in volts,where the ratio $a/b$ is $700^{\circ}C$. If the cold junction is kept at $0^{\circ}C$,then the neutral temperature is:

$A$ cable consists of a copper wire of radius $9 \, mm$ having a resistance of $5 \, \Omega$. If this cable is replaced by $6$ copper wires each of radius $3 \, mm$,what will be the new resistance of the cable in $\Omega$?

The Peltier coefficient for the junction of a pair of metals is proportional to:

In order to determine the $e.m.f.$ of a storage battery,it was connected in series with a standard cell in a certain circuit,and a current $I_1$ was obtained. When the battery is connected to the same circuit opposite to the standard cell,a current $I_2$ flows in the external circuit from the positive pole of the storage battery. What is the $e.m.f.$ $\varepsilon_1$ of the storage battery? The $e.m.f.$ of the standard cell is $\varepsilon_2$.

In the circuit shown below,the resistance and the emf source are both variable. The graph of seven readings of the voltmeter and the ammeter ($V$ and $I$,respectively) for different settings of resistance and the emf,taken at equal intervals of time $\Delta t$,are shown below by the dots connected by the curve $EFGH$. Consider the internal resistance of the battery to be negligible and the voltmeter and ammeter to be ideal devices. (Take $R_0 = \frac{V_0}{I_0}$). Then,the plot of the resistance as a function of time corresponding to the curve $EFGH$ is given by:

If the internal resistance of a cell is proportional to the current drawn from the cell,then the best representation of the terminal potential difference of the cell with respect to the current drawn from the cell will be: