Alessandro Volta invented electric battery. It was first named as Voltaic Pile. For his contributions to science, the unit of electric potential is named as Volt. John Frederic Daniell developed Daniell cell. Copy the link given below and paste it in new browser window to get more information on Cells in Series and in Parallel www.askiitians.com/iit-jee-electric-current/cells-in-series-and-in-parallel/

1. Cells in Series and
parallel

2. Contents
The beginning of cell
Cell or battery
EMF and internal resistance
Combination of cells in series connection
Combination of cells in parallel connection

3. History
• Alessandro Volta invented electric battery known as Voltaic pile.
• John Frederic Daniell - developed Daniell cell.
• George Leclanche invented Wet cell.
• Dr. Carl Gassner introduced the Dry cell battery.
• Gaston Plante introduced the first rechargeable battery.

4. Cell or battery
• A cell or battery is the one which can convert chemical energy into
electrical energy. They provide a convenient source of energy to
energize devices without cables and wires
• A cell consists of three parts.
• Electrodes - A positive terminal and negative terminal. The positive
terminal of the cell is called cathode and the negative terminal of
the cell is called anode.
• Electrolyte- a chemical solution.

5. Emf and Internal resistance
• EMF or electromotive force is the potential difference developed
between the two terminals of a battery in an open circuit.
• ε = E/Q, where ε is the electromotive force, E is the energy and Q is
the charge.
• Internal resistance is the resistance that resists the current flow
when connected to a circuit.
• V = ε – Ir is the equation which connects emf and internal
resistance. where V is the potential difference across the circuit, ε is
the emf, I is the current flowing through the circuit, r is internal
resistance.
• The terminal potential difference is the potential difference
between the positive and negative terminals of the cell when
current flows in the circuit.

6. Combination of cells in series connection
• For the two cells connected in series the voltage developed is V = (ε1
+ ε2) – I (r1+r2). V = εeq - req if we replace the number of cells by a
single cell.

7. Combination of resistors in parallel connection
For the two cells connected in parallel V = ε1 r2 + ε2 r1/ r1+ r2 – Ir1r2 /
r1+ r2. For n number of cells connected in parallel
εeq / req = ε1 / r1 + ε2 / r2 +…… εn / rn.

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