In practical application, the resistance value of 100 ohm means that when the voltage is 1 volt, the current through the resistor is 0. 1 amp. This is because the size of the resistance determines the resistance when the current passes. The greater the resistance, the smaller the current. Conversely, the smaller the resistance, the greater the current.

Ohm's law is a physical quantity that describes the conductivity of a conductor. The mathematical expression of ohm's law is: I=U divided by r, where I stands for current, u stands for voltage and r stands for resistance.