The $emf$ of a thermocouple, with one junction kept at $0^{\circ}C$, is given by the equation $e = at + bt^2$. The Peltier coefficient is given by:

If the temperature of the cold junction of a thermocouple is lowered,then the neutral temperature

Answer the following questions:
$(a)$ $A$ steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor: current, current density, electric field, drift speed?
$(b)$ Is Ohm's law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm's law.
$(c)$ $A$ low voltage supply from which one needs high currents must have very low internal resistance. Why?
$(d)$ $A$ high tension $(HT)$ supply of, say, $6 \ kV$ must have a very large internal resistance. Why?

The figure shows a network of four resistances and three batteries. The electrical power dissipated as heat in the circuit is .............. $W$.

If in the circuit shown below,the internal resistance of the battery is $1.5 \, \Omega$ and $V_P$ and $V_Q$ are the potentials at $P$ and $Q$ respectively,what is the potential difference between the points $P$ and $Q$?

For a thermocouple,the neutral temperature is $270\,^\circ C$ and the temperature of its cold junction is $20\,^\circ C$. If there is no deflection in the galvanometer,the temperature of the hot junction should be .............. $^\circ C$