There are seven colors in rainbow: violet, indigo, blue, green, yellow, orange and red. The acronym VIBGYOR is a famous mnemonic to remember the colors. The rainbow is formed by reflection, refraction and dispersion of light through water droplets suspended in the air or through a prism. When the Sun light enters a droplet, the light refracted (bent) and reflected inside the droplet and refracted again as it leaves the droplet, this phenomenon forms the rainbow. Rainbow takes the form of a multi colored arc or it can be full circle.