What is $emf$?

If the reduction potential is more,then

The standard electrode potential $(E^\circ)$ for the reaction $Zn^{2+}_{(aq)} + 2e^- \rightarrow Zn_{(s)}$ is $-0.76 \ V$. What is the standard electrode potential for the reaction $2Zn_{(s)} \rightarrow 2Zn^{2+}_{(aq)} + 4e^-$?

The $E^{\ominus}$ for $Cl_{2}/Cl^{-}$ is $+1.36 \ V,$ for $I_{2}/I^{-}$ is $+0.53 \ V,$ for $Ag^{+}/Ag$ is $+0.79 \ V,$ $Na^{+}/Na$ is $-2.71 \ V$ and for $Li^{+}/Li$ is $-3.04 \ V.$ Arrange the following ionic species in decreasing order of reducing strength: $I^{-}, Ag, Cl^{-}, Li, Na$

Which of the following has been universally accepted as a reference electrode at all temperatures and has been assigned a value of zero volt?

Using the standard electrode potential values,which of the following statements $(I, II, III, IV)$ is/are correct?
$Fe^{2+}_{(aq)} + 2e^{-} \rightleftharpoons Fe_{(s)}$ ; $E^o = -0.44 \, V$
$Cu^{2+}_{(aq)} + 2e^{-} \rightleftharpoons Cu_{(s)}$ ; $E^o = +0.34 \, V$
$Ag^{+}_{(aq)} + e^{-} \rightleftharpoons Ag_{(s)}$ ; $E^o = +0.80 \, V$
$I$. Copper displaces iron from $FeSO_4$ solution.
$II$. Iron displaces copper from $CuSO_4$ solution.
$III$. Silver displaces copper from $CuSO_4$ solution.
$IV$. Iron displaces silver from $AgNO_3$ solution.