Which among the following is a standard cell ?
Which among the following is a standard cell ?
The correct option is C Cadmium cell
The ideal qualities of standard cells as follows:
(1) The cells must be constructed from high purity materials and be reproducible.
(2) Except when current is flowing there should be no chemical reaction taking place in the cell.
(3) When the cell is thermally cycled it must give the same emf at a given temperature regardless of its thermal history.
(4) When a current is passed through the cell, its emf may change, but it must recover rapdidly and completely on cessation of the current.
(1) to (4) above represent an ideal qualities which only the Weston Standard cell approaches. The Weston Standard cell is constructed with the basic materials- mercury, cadmium, sulfuric acid, and water- are all purified by distillation, starting with the purest materials available. Hence out of given cells cadmium cell is the standard cell.
The ideal qualities of standard cells as follows:
(1) The cells must be constructed from high purity materials and be reproducible.
(2) Except when current is flowing there should be no chemical reaction taking place in the cell.
(3) When the cell is thermally cycled it must give the same emf at a given temperature regardless of its thermal history.
(4) When a current is passed through the cell, its emf may change, but it must recover rapdidly and completely on cessation of the current.
(1) to (4) above represent an ideal qualities which only the Weston Standard cell approaches. The Weston Standard cell is constructed with the basic materials- mercury, cadmium, sulfuric acid, and water- are all purified by distillation, starting with the purest materials available. Hence out of given cells cadmium cell is the standard cell.
