Gamma rays travel faster than visible light. All electromagnetic waves travel at the same speed in a vacuum. Any warm object emits this wave.

Gamma rays have the highest frequency. Radio waves have the longest wavelength. None of those present has the highest speed. All photons travel at the same speed, at the speed of light, regardless of energy.

Ultraviolet radiation has shorter waves than blue or violet light, and thus oscillates more rapidly and carries more energy per photon than visible light does. Light travels at a speed of 299,792 kilometers per second (about 186,282 miles per second). Different colors of light bend by slightly different amounts.

So according to equation (1) velocity of light is directly proportional to the wavelength. So violet color has minimum velocity of light and red color has maximum velocity of light when it passes through the glass. Hence the red color of white light travels fastest in the glass.

Light, no matter how high-or-low in energy, always moves at the speed of light, so long as it’s traveling through the vacuum of empty space. And to the best of our knowledge and measurements, the speed of light has the same value of 299,792,458 m/s at all times and all locations in the Universe.

and since we know that violet lightis refracted by more angle than red light , hence lateral shift of violet light is maximum.

The refractive index is maximum for the colour corresponding to the lowest possible wave length in the visible spectrum. The refractive index is maximum for violet colour.

The refractive index of a medium (sometimes called the index of refraction) is used to calculate the change in speed or direction as light travels from one transparent medium into another….An overview of refraction and wavelength.