<p> “RESISTANCE is futile” (7 of 9 Star Treck Voyager)</p><p>Which road allows cars to move more easily?</p><p>Which pipe would be easier to crawl through?</p><p>Electrical Resistance is like this. Conductors allow electrons to move through them. The ease at which the electrons can move depends on:</p><p> The material the conductor is made of - gold is the best conductor</p><p> The length of the conductor</p><p> The diameter of the conductor  The temperature of the conductor – cold conductors allow electricity to flow easier than hot.</p><p>The energy that is used to push a coulomb of charge through a light bulb filament depends on the resistance of the filament.</p><p>Electrical resistance is defined as: the ratio of potential difference across the load (V) to the current through the load (I)</p><p>R is used to represent resistance and is measured in units called OHMS (Ω)</p><p>R = V resistance = potential difference I current</p><p>The OHM is honour of Sir Georg Simon Ohm (1789 – 1854). Ohm was the first person to publish the results of his experiments on resistance. His observations are now called Ohm’s Law. The mathematical formula for this law is:</p><p>V = IR - Ohm’s Law</p><p>Any resistor that has a constant resistance is known as an Ohmic resistor.</p>