When white light is dispersed into its seven-colour components by a prism, which color of light bends the least?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Red
Dispersion happens because glass has a slightly different refractive index for each colour: the longer the wavelength, the smaller the refractive index and the less the light bends. Red has the longest wavelength of the visible colours, so it is deviated the least; violet, with the shortest, is deviated the most.
That is why the spectrum from a prism always runs in the order VIBGYOR from the most bent to the least bent: violet, indigo, blue, green, yellow, orange, red. Yellow and green lie in the middle of this order.