Write any two factors on which internal resistance of a cell depends .The reading on a high resistance voltmer,where a cell is connected across it , is 2.2 V. When the terminals of the cell are also connected to a resistance of 5 `Omega` as shown in the circuit , the voltmeter reading drops to 1.8 V .Find the interval resistance of the cell.

Explanation

Internal resistance of a cell depends upon the following factors :
(i) Distance between the electrodes .
(ii) The nature of the electrolyte .
(iii) The nature of electrodes .
Area of the electrodes , immersed in the electrolyte . If area increases , internal resistance decreases .
(b) Given : emf of cell , `epsi = 2.2 V , R = 5 Omega , V = 1 . 8 V`
`r = ((epsi)/(V) - 1) R implies ((2.2)/(1.8) - 1) xx 5 = ((2.2 - 1.8)/(1.8)) xx 5`
`therefore " " r = (0.4)/(1.8) xx 5 = (2)/(1.8) = 1.1 Omega`.