You are given a cell whose internal resistance is to be calculated. Obtain an expression for calculating the internal resistance.

You are given two cells. Group them so that they give more voltage. Arrive at the expression for effective emf and internal resistance.

Write down the relation between the emf of cell and its internal resistance.

How would you arrange 48 cells each of emf 1.8V and internal resistance 1Omega , so as to get strongest possible current in a resistance of 3Omega . (n-series, m-rows)