As the temperature of the hot junction of a thermocouple is increased (while the cold junction is at a constant temperature), the thermo $e.m.f.$

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?

Consider the following statements $A$ and $B$ and identify the correct answer given below.
$A$. Peltier coefficient is numerically equal to the potential difference across the junctions of the thermocouple through which current is flowing.
$B$. According to Thomson, energy is neither absorbed nor evolved at the junction of a thermocouple but is absorbed or evolved only along the lengths of both the conductors.

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.

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 $Q$?

In the circuit shown here,the readings of the ammeter and voltmeter are