Which of the following statements is true for fuel cells?

If less than $1.1 \ V$ external opposite current is passed through the Daniell cell,for such condition answer the following questions :
$(1)$ Which are anode and cathode ?
$(2)$ Give direction for electron and current flow.

Efficiency of a cell with cell reaction under standard conditions is $70\%$. Cell reaction:
$A_{(s)} + B^{\oplus} \longrightarrow A^{\oplus} + B_{(s)}$ ; $\Delta H^o = -551.5 \ kJ$. Calculate standard electrode potential of cell (in $volt$).

Which of the following is not used to construct a salt bridge?

Assertion : If $\lambda^o_{Na^{+}}$ and $\lambda^o_{Cl^{-}}$ are molar limiting conductivity of sodium and chloride ions respectively,then the limiting molar conductivity for sodium chloride is given by the equation :
$\Lambda^o_{NaCl} = \lambda^o_{Na^{+}} + \lambda^o_{Cl^{-}}$
Reason : This is according to Kohlrausch law of independent migration of ions.

What are the uses of the $Ni-Cd$ cell?