When I connect a cell with 100 Ω resistor. voltage across circuit is 1.4 V and current is 14 mA. That means total power of cell is 1.41 x 0.014 = around 20 mW. Right?
Now if I connect two cells in series with same 100 Ω resister the volts across are 2.83 V and current is 27.6 mA
If we multiply them we get around 78 mW.
What I don't understand is if one cell has around 20 mW of power how come two cells have 78 mW instead of double of 20 mW = 40 mW maybe?