How long can spark plugs last? There are two types of spark plugs: conventional and long-life (platinum- or iridium-tipped). Conventional spark plugs need to be replaced every 30,000-50,000 miles. Recommended replacement intervals for iridium- or platinum-tipped spark plugs vary between 50,000 and 120,000 miles. To find out the recommended replacement interval for your car, check your maintenance schedule.
Its key principles: (1) the three primary colors are red, yellow and blue, (2) the primaries exist as three material substances (often identified with specific pigments), (3) the primaries cannot be mixed from other colors, but can mix all other colors.
All of the wavelengths present in visible light form colorless white light when they are combined, but can be refracted and dispersed into their individual colors by means of a prism. The colors red, green, and blue are classically considered the primary colors because they are fundamental to human vision. All other colors of the visible light spectrum can be produced by properly adding different combinations of these three colors. Moreover, adding equal amounts of red, green, and blue light produces white light and, therefore, these colors are also often described as the primary additive colors.