What is electrode potential?

For the following cell,the standard electrode potential $E_{cell}^0$ is . . . . . . .
$E_{Zn^{2+}/Zn}^0 = -0.76 \ V, E_{Cu^{2+}/Cu}^0 = 0.34 \ V$
$Zn | Zn^{2+} || Cu^{2+} | Cu$ (in $V$)

Calculate the $Zn-Cu$ cell (Daniell cell) potential. Given: $E^o_{Zn^{2+}|Zn} = -0.76 \ V$ and $E^o_{Cu^{2+}|Cu} = 0.34 \ V$. (in $V$)

Which one among the following is the strongest reducing agent?
$Fe^{2+} + 2e^- \to Fe \ (E^\circ = -0.44 \ V)$
$Ni^{2+} + 2e^- \to Ni \ (E^\circ = -0.25 \ V)$
$Sn^{2+} + 2e^- \to Sn \ (E^\circ = -0.14 \ V)$
$Fe^{3+} + e^- \to Fe^{2+} \ (E^\circ = +0.77 \ V)$

Which of the following is the weakest reducing agent?

The standard reduction potentials for $Zn^{2+}/Zn$,$Ni^{2+}/Ni$ and $Fe^{2+}/Fe$ are $-0.76 \ V$,$-0.23 \ V$ and $-0.44 \ V$ respectively.
The reaction $X + Y^{2+} \rightarrow X^{2+} + Y$ will be spontaneous when: