Electric Cells & EMF

V = E - Ir = 2.5\ V

Bank EMF3.00 V

Bank internal resistance0.40 Ω

Current1.25 A

Terminal voltage2.50 V

Number of cells2

EMF per cell (V)1.5

Internal resistance per cell (Ω)0.2

External resistance (Ω)2

With current flowing, confirm the terminal voltage is less than the EMF
Set 4 cells in series with EMF 1.5 V each — confirm the bank EMF reads exactly 6 V
Set 4 cells in parallel — confirm the bank EMF is still just one cell's EMF
Compare 4 cells in parallel against a single cell — confirm the internal resistance has dropped to a quarter
With 4 cells in series (vs 1), confirm more current flows through the same external resistance