In a silver voltameter, $2.89 \ g$ of silver is deposited in $10 \ minutes$. The heat produced in a $20 \ \Omega$ resistor for the same time will be ................ $kJ$.

Statement $(I)$: The temperature coefficient of resistance for most metals in pure form is positive.
Statement $(II)$: $A$ metal wire $2 \ mm$ in diameter carries a charge of $360 \pi \ C$ in two hours. If the metal contains $5 \times 10^{22}$ free electrons $/ cm^3$, then the drift velocity of the electrons in the wire is $6.25 \times 10^{-6} \ m/s$.
Statement $(III)$: Semiconductors like pure germanium do not obey Ohm's law for all ranges of electric field values. Which of the following is correct?

The heat evolved or absorbed at the junction when an electric current passes through the junction of two different metals is known as which effect?

Assertion: In a simple battery circuit,the point of the lowest potential is the positive terminal of the battery.
Reason: The current flows towards the point of the higher potential,as it does in such a circuit from the negative to the positive terminal.

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 $^{\circ} C$)?

The value of the resistance $R$ in the figure is adjusted such that the power dissipated in the $2\,\Omega$ resistor is maximum. Then the power dissipated in the $2\,\Omega$ resistor will be ................ $W$.