The two ends of a conductor are connected to a cell having an $e.m.f. \ E$ and some internal resistance. Starting from the midpoint $P$ of the conductor,moving in the direction of the current,and returning to point $P$,which of the following graphs best represents the potential $V$ versus the distance $x$ covered along the path?

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

Consider a block of conducting material of resistivity $\rho$ shown in the figure. Current $I$ enters at $A$ and leaves from $D$. We apply the superposition principle to find the voltage $\Delta V$ developed between $B$ and $C$. The calculation is done in the following steps: $(i)$ Take current $I$ entering from $A$ and assume it to spread over a hemispherical surface in the block. $(ii)$ Calculate the field $E(r)$ at distance $r$ from $A$ by using Ohm's law $E=\rho j$,where $j$ is the current per unit area at $r$. $(iii)$ From the $r$ dependence of $E(r)$,obtain the potential $V(r)$ at $r$. $(iv)$ Repeat $(i), (ii)$ and $(iii)$ for current $I$ leaving $D$ and superpose results for $A$ and $D$. $\Delta V$ measured between $B$ and $C$ is

For a thermocouple,the inversion temperature is $600^{\circ} C$ and the neutral temperature is $320^{\circ} C$. Find the temperature of the cold junction (in $^{\circ} C$)?

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:

$A$ battery consists of a variable number $n$ of identical cells,each having electromotive force $E$ and internal resistance $r$,connected in series. The terminals of the battery are short-circuited,and the current $I$ is measured. Which one of the graphs below shows the relationship between $I$ and $n$?