Why the refractive index of a medium does not depends upon the frequency of light. As it is the ratio of Wavelength of light in first medium to the wavelength of light in second medium.Please help me in understanding this concept..

When a light ray tavels from one medium to another then frequency remains constant since it depends only on source . Velocity =frequency× wavelength .here speed changes and wavelength too .n= c/v of medium then putting value of velocity we will get the desired ratio mentioned in question.