# Will the focal length of a lens for red light be more, same or less than that for blue light?

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Will the focal length of a lens for red light be more, same or less than that for blue light?

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As the refractive index for red is less than that for blue, parallel beams of light incident on a lens will be bent more towards the axis for blue light compared to red. Thus the focal length for blue light will be smaller than that for red.