What is Newton’s Disc

Newton’s disc is a coloured disc which is painted with the colours of white light [i.e., violet, indigo, blue, green, yellow, orange, and red (VIBGYOR)] in equal proportions so that when it is rotated very fast, the disc appears white. This is because of a property of our eyes called persistence of vision. This means that an image formed by the eye remains for a fraction of a second. When the disc is rotated at a high speed, the images of the different colours overlap in our eyes and the brain perceives it as white.