Inside Cutson glass

Orange light travels faster than yellow light Yellow light travels faster than orange light Orange and yellow light ravels equally fast We cannot determine which colour of light travels faster

Orange light travels faster than yellow light

The velocity of light is inversely proportional to the index of refraction v = $\frac{c}{n}$, So, the lower the n, the higher the v. According to table, Cutson glass has a slightly lower n for orange light than it has for yellow light. Therefore, inside Cutson glass, orange light travels slightly faster.