When the computer receives a rich signal (high voltage) from the O2 sensor, it leans the fuel mixture to reduce the sensor's reading. When the O2 sensor reading goes lean (low voltage), the computer reverses again making the fuel mixture go rich.
Chemistry and physics are branches of science that both study matter. The difference between the two lies in their scope and approach. Chemists and physicists are trained differently, and they have different professional roles, even when working in a team.
Chemistry, from the ancient Egyptian word khÄmia meaning transmutation of earth, is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals.