Define Peltier coefficient. Give its unit.

Hint: In this question we will define the peltier coefficient with the help of the relation between the heat absorbed at a junction, current flowing at a time. This will help us answer the question. For further better understanding we will discuss the basics of current and a circuit.

Formula used:
$H = \pi It$

Complete step by step solution:
 Here, we know that the amount of heat energy absorbed or evolved at any one of the junctions of a thermocouple when one ampere of current flows for one second is called the Peltier coefficient.
It is denoted by $\pi $ . Further, the unit of Peltier is volt. If H is the quantity of heat absorbed or we can say evolved at one junction, then this is given as:
$H = \pi It$

Additional Information: We know that an electric current can be defined as a stream of charged particles, such as electrons or ions, which are moving through an electrical conductor or we can say space. Current is measured as the net rate of flow of electric charge in a region. The S.I unit of an electric current is ampere, which is denoted by A.
In a circuit if the resistance is constant over a range of voltage, then I = V/R, can be used to predict the behavior of the material. This involves DC current and voltage, it is the same for the resistors. Further, a material obeys Ohm's law or does not obey; the resistance of the material can be described in terms of its bulk. The resistivity, and the resistance both, is temperature dependent. Over certain ranges of temperature, this temperature dependence can be predicted from resistance.

Note: In series connection the resistances are directly added whereas in parallel connection resistance is added inversely. Internal resistance of a circuit refers to the opposition to the flow of current offered by the cells and batteries themselves thereby, resulting in the generation of heat. Internal resistance and resistance both are measured in Ohms.