Define electrode potential and derive Nernst's equation for it ?

Electrode Potential :-

Electrode potential is defined as the potential difference between electrode and electrolyte in which electrode is present in it.
                                         If a metal electrode is dipped in solution of its own ion then the potential difference is arises between electrode and its solution them this potential difference is known as Electrode potential.

Derive Nernst Equation :-

Nernst equation gives relationship between electrode potential of an electrode.

                Let us see how Nernst equation derive: -                                          

Let us consider a reversible equation –

This answer is enough for university exam.