Why does the cross-sectional area of a wire affect its resistance?
Think of the wire as a water pipe leading to a tap and the electricity as water (in fact many early engineers called it “juice”). Electrical voltage (Volts) would be similar to pressure, and Electrical current (Amps) would be similar to flow. Electrical resistance (Ohms) is just the ratio Volts/Amps. When we fully open a tap, water will pour though. Lets call the flow of water 1A. The rate of flow will depend on water pressure more water will flow at high pressure. Lets call the pressure 1V. The resistance of one water pipe is then simply 1V/1A or 1 Ohm. Partially closing the tap until the flow (current) becomes halved (.5A) will increase the resistance of the pipe to 1V/0.5A = 2 Ohm. Now consider several water pipes with taps, such as in a public washroom. If the pressure (V) stays constant, then opening 2 taps at the same time will result in twice the flow rate (2A) so the resistance of the two pipes working together in parallel is reduced to 1V/2A = 0.5 Ohm. We could get a similar g
