Concepts to Remember on Series and Parallel Combinations of Cells:

• Electric circuit: A closed loop or path through which electric current can flow.
• Cell: A device that converts chemical energy directly into electrical energy.
• Difference between series and parallel circuits:
  • Series circuit: Components are connected in a single pathway.
  • Parallel circuit: Components are connected along multiple pathways.
• Potential difference (voltage): The difference in electric potential between two points.
• Current: The flow of electric charges through a conductor.
• Resistance: Property of a material that opposes the flow of electric current.
• Ohm’s law: Mathematical relationship between voltage, current, and resistance.
• Kirchhoff’s current law: The total current entering a junction is equal to the total current leaving that junction.
• Kirchhoff’s voltage law: The sum of the voltages around any closed loop in a circuit must equal zero.
• Types of cells:
  • Primary cells: Non-rechargeable cells, e.g., zinc-carbon battery.
  • Secondary cells (rechargeable batteries): Rechargeable cells, e.g., lead-acid battery, lithium-ion battery.
• Internal resistance: Resistance within a cell that opposes the flow of current.
• Electromotive force (emf) of a cell: Energy per unit charge supplied by a cell.
• Terminal potential difference: Voltage across the terminals of a cell.
• Combinations of cells: Connecting cells together to obtain desired voltage and/or current.
• Advantages and disadvantages:
  • Series combinations:
    • Advantage: Higher voltage.
    • Disadvantage: Reduced current, one open cell breaks the circuit.
  • Parallel combinations:
    • Advantage: Higher current.
    • Disadvantage: Lower voltage, one open cell does not affect the circuit.