Final answer:
Ohm's law describes the direct relationship between voltage and current and the inverse relationship between current and resistance in electric circuits. Voltage produces current, which is impeded by resistance, affecting the circuit's power consumption or transformation.
Step-by-step explanation:
The relationships between voltage, resistance, and current in an electric circuit are described by Ohm's law. Voltage is the cause that generates current, which is the effect. As the relationship suggests, voltage (V) across an electrical device is equal to the product of the current (I) flowing through it and the resistance (R) of the device (V = IR). Additionally, resistance is defined as inversely proportional to current, implying that if resistance doubles, current is cut in half, assuming constant voltage.
For ohmic devices - those which follow Ohm's law linearly - these relationships are consistent and predictable. Resistors, which impede current similar to how friction impedes movement, have a resistance that determines the amount of current for a given voltage. The relationship can also be represented graphically, with the slope of the line representing resistance on a current versus voltage graph.
To calculate power (P), you can use the relationships P = VI, P = V2/R, or P = I2R. This is useful for understanding how energy is consumed or transformed within an electrical circuit.