$K,$ $Ca,$ and $Li$ metals may be arranged in the increasing order of their standard electrode potentials as

$A$ galvanic cell with electrode potential of $A = + 2.23 \ V$ and $B = - 1.43 \ V$. The value of $E^o_{cell}$ is .............. $V$.

Standard oxidation potentials $(SOP)$ of four metals $P, Q, R$ and $S$ are $+2.87 \ V, +3.05 \ V, -0.80 \ V$ and $+0.25 \ V$ respectively. The reducing power of these metals is:

Given $E_{Cu^{2+}/Cu^{+}}^o = 0.15 \, V$,$E_{Cu^{2+}/Cu}^o = 0.34 \, V$. The standard electrode potential for the half-cell $Cu^{+}/Cu$ is ............. $V$.

Consider the following relations for $EMF$ of an electrochemical cell:
$(i)$ $EMF$ of cell = (Oxidation potential of anode) $-$ (Reduction potential of cathode)
$(ii)$ $EMF$ of cell = (Oxidation potential of anode) $+$ (Reduction potential of cathode)
$(iii)$ $EMF$ of cell = (Reduction potential of anode) $+$ (Reduction potential of cathode)
$(iv)$ $EMF$ of cell = (Oxidation potential of anode) $-$ (Oxidation potential of cathode)
Which of the above relations are correct?

What is cell potential and $emf$? Explain with suitable examples.