Magnifying power of microscope \(∝ \frac{1}{f_o f_e}\)
where \(f_o\) and \(f_e\) are the focal lengths of objective lens and eyepiece lens.
Focal length of a lens depends upon the refractive index and different colour of light has different refractive index with respect to the medium of lens material. Hence magnifying power of a microscope depends on the colour of the light used.
