```why does red light travel faster than violet light , though violet light has more energy (in glass)? plz give a simple answer which can be understood by a 10th class student.
Actually all light travels at the same speed. The difference is the wavelength so red light goes further into a substance before it is bent or refracted.
When light enters a prism the light is bent as the crest or peaks of energy encounter the glass. Violet light has the shortest wavelengths so the violet light's peaks encounter the glass first and are bent first. The red light has the longest wavelengths so the crests or peaks encounter the glass last and are the last to be bent.
All light travels at the same speed but it takes longer for the longer wavelengths like red to be bent by a prism.