Suppose the drift velocity $v_d$ in a material varies with the applied electric field $E$ as $v_d \propto \sqrt{E}$. Then the $V-I$ graph for a wire made of such a material is best given by:

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:

$A$ battery of $emf$ $E$ and internal resistance $r$ is connected across a resistance $R$. Resistance $R$ can be adjusted to any value greater than or equal to zero. $A$ graph is plotted between the current $(i)$ passing through the resistance and potential difference $(V)$ across it. Select the correct alternative$(s)$.

$A$ room has an $AC$ running for $5$ hours a day at a voltage of $220$ $V$. The wiring of the room consists of $Cu$ wire of $1$ $mm$ radius and a length of $10$ $m$. Power consumption per day is $10$ commercial units. What fraction of it goes into Joule heating in the wires? What would happen if the wiring is made of aluminium of the same dimensions? $(\rho_{Cu} = 1.7 \times 10^{-8} \, \Omega m, \rho_{Al} = 2.7 \times 10^{-8} \, \Omega m)$

Three identical resistors are connected in series,and the total power consumed is $10 \, W$. If they are connected in parallel,what will be the total power consumed in $W$?

$A$ certain charge liberates $0.8\, gm$ of ${O_2}$. The same charge will liberate how many $gm$ of silver?