If the cold junction is held at $0^{\circ} C$, the thermo emf $V$ of a thermocouple varies as $V = 10 \times 10^{-6} t - \frac{1}{40} \times 10^{-6} t^2$, where $t$ is the temperature of the hot junction in $^{\circ} C$. The neutral temperature and the maximum value of thermo emf are respectively:

$A$ wire of length $L$ and $3$ identical cells of negligible internal resistances are connected in series. Due to current,the temperature of the wire is raised by $\Delta T$ in a time $t$. $A$ number $N$ of similar cells is now connected in series with a wire of the same material and cross-section but of length $2L$. The temperature of the wire is raised by the same amount $\Delta T$ in the same time $t$. The value of $N$ is

Which of the following circuits follows Ohm's law?

For a given temperature difference,which of the following pairs will generate maximum thermo $e.m.f.$?

The Peltier coefficient is $2 \times 10^{-9} \, V$. How much heat in $ergs$ is produced when a current of $2.5 \, A$ is passed for $2 \, minutes$?

An electric kettle has two coils. When one coil is switched on,the tea gets heated in $10 \, \text{min}$. When the other coil is switched on,the same amount of tea gets heated in $40 \, \text{min}$. If both coils are connected in parallel,how long will it take to heat the same amount of tea (in $, \text{min}$)?