What is calomel electrode?

The ${\left(\frac{\partial \mathrm{E}}{\partial \mathrm{T}}\right)}_{\mathrm{P}}$ of different types of half cells are as follows :
$\begin{array}{cccc}\mathrm{A}& \mathrm{B}& \mathrm{C}& \mathrm{D}\\ 1\times {10}^{-4}& 2\times {10}^{-4}& 0.1\times {10}^{-4}& 0.2\times {10}^{-4}\end{array}$

(Where $\mathrm{E}$ is the electromotive force). Which of the above half cells would be preferred to be used as reference electrode

Some materials are given below:

Write the chemical equation fo the reaction taking place at the cathode.

Some materials are given below:

Which is the anode of this cell?

An article made of copper is to be electroplated with silver.

What should be the cathode and the anode made up of?

Depict the galvanic cell in which the reaction

$\mathrm{Z}\mathrm{n}\left(\mathrm{s}\right)+2\mathrm{A}{\mathrm{g}}^{+}\left(\mathrm{a}\mathrm{q}\right)\to \mathrm{Z}{\mathrm{n}}^{2+}\left(\mathrm{a}\mathrm{q}\right)+$$2\mathrm{A}\mathrm{g}\left(\mathrm{s}\right)$ takes place. Further show:
Which of the electrode is negatively charged?