I have studied current electricity for a while now. When I look back at basic concepts, I am quite clear about what current, electron, resistance is. But I cannot imagine about the potential difference or voltage of a battery. Or in a circuit, it is said that potential drops across a resistance, why is that so?
What does it mean to have a potential difference? I asked my friends too, but none of them have quite understood the concept too. So, can you clarify the concept of p.d? using analogies or any way that might easy.
[Physics] Potential Difference of a battery – What does it mean
batterieselectric-circuitselectrical-resistancepotentialvoltage
Best Answer
Basically it all comes down to potential energy. A battery supplies electrical potential energy that can enable electrical current to flow. The source of the battery’s energy is conversion of chemical energy. An analogy is a water pump supplies mechanical potential energy that can enable water to flow.
If no circuit is connected to a battery, or if a switch connecting a circuit is open, no electrical current will flow. But the potential still exists, as there will be a voltage across the batter terminals. If a water pump is running but a valve connecting a piping system is closed, no water will flow. But the potential still exists, since the pump supplies mechanical pressure upstream of the valve. In this sense, mechanical pressure (mechanical potential) is analogous to electrical voltage (electrical potential).
When the battery is connected to a closed circuit, current will flow. The current will encounter electrical resistance causing voltage to drop (a loss in potential energy). The loss of potential energy in the resistor equals the heat generated by the resistor. This is the basis of Kirchhoff’s voltage law, which states the algebraic sum of the voltages in a closed circuit equals zero. It is basically a statement of conservation of energy.
When the water valve is opened water will flow. The water flow will encounter pipe resistance resulting it water pressure to drop (a loss in mechanical potential energy) along the length of the pipe.
Hope this helps.