If less than $1.1 \ V$ external opposite current is passed through the Daniell cell,for such condition answer the following questions :
$(1)$ Give reaction of cathode,anode and redox.
$(2)$ Between $Zn$ and $Cu$ which metal dissolve in solution ?

(N/A) When an external potential $E_{ext} < 1.1 \ V$ is applied to a Daniell cell,the cell continues to function as a galvanic cell.
$(1)$ The reactions are:
Anode reaction: $Zn(s) \rightarrow Zn^{2+}(aq) + 2e^-$
Cathode reaction: $Cu^{2+}(aq) + 2e^- \rightarrow Cu(s)$
Redox reaction: $Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s)$
$(2)$ Since $Zn$ is the anode,$Zn$ metal dissolves into the solution as $Zn^{2+}$ ions.