Water pressure in a hose
Voltage is like the water pressure pushing through a hose, current is how much water flows, and a kink in the hose is resistance. Ohm's law ties them together: squeeze the hose and less water flows for the same push.
The plumbing analogy
An electric current is a flow of charge through a circuit. Voltage (V) is the push that drives it, current (I) is the rate of flow in amperes, and resistance (R) opposes the flow in ohms. Ohm's law ties them together: V = I × R.
Water helps the intuition
Think of voltage as water pressure, current as the flow rate, and resistance as a narrow pipe. More pressure or a wider pipe means more flow.
A 12 V battery across a 4 Ω resistor drives a current of I = V/R = 12/4 = 3 amperes.
Lab · Solve for resistance
- A circuit carries 2 A when driven by 10 V.
- Rearrange Ohm's law to solve for R.
- Compute the resistance.
What you should see: R = V/I = 10/2 = 5 ohms.