Does ultra violet / infra red and normal light travel at the same speed if not which is fastest?

All the lights you mentioned are all parts of the same thing: Electromagnetic Wave. Take an automobile for example, we know it's made of several parts; as it moves, all it's parts move at the same speed. You won't ask if the hood is moving at the same speed as the trunk, would you?



To get a better grasp of the Electromagnetic wave spectrum, imagine yourself at a window looking at a tree trunk (stem). You know the tree has roots as well as leaves but at the moment, only the trunk is visible to you. This is the visible light (what you called 'normal light'), so called because it is 'visible' to you. Take the lower portion of the tree, that are out of range of your vision, to be the 'infra' part while the upper portion, that are also out of range, as the 'ultra' part.



There, you see all the lights you mentioned are all parts of a whole, called The Electromagnetic Spectrum and they all move at the same speed of 3 * 10^8 m/s.

Does ultra violet / infra red and normal light travel at the same speed if not which is fastest?
...maybe, but it never mentions "in a vacuum"!



This is important e.g. through glass (prism) or water (rain drops), the difference in velocity with frequency is the reason you see the colours of the rainbow!!!!! Report It
Reply:They all travel at the same speed. So do microwaves, radio waves, X-rays, TV signals (through the air), and gamma radiation.
Reply:Light of all types in the electromagnetic spectrum travel at the same speed.....186,292 miles a second.
Reply:The index of refraction differs not the velocity.

http://en.wikipedia.org/wiki/Refractive_...
Reply:All light travels at the same speed. The differences in color are the result of the wavelengths of the light. Wavelengths are the measure of the waves of light as they travel. The visible spectrum of light for humans is between red and violet. Untraviolet is too hig a wavelength for us to see unassisted, whereas infrared is too low a wavelength.
Reply:The speed of light is always the speed of light.
Reply:They all travel at the speed of light, then only difference between them is the frequency.
Reply:All electromagnetic waves (radio, xray, gamma ray, light, ultraviolet, infrared, microwave, etc) travel at the same speed- the speed of light- or about 300 thousand kilometers (186000 miles) per second, in a vacuum.



However in gasses, liquids, or transparent solids, they DO seem to propagate at different speeds- that is what makes a rainbow or a prism spread light into bands by wavelength. It's called dispersion. Higher wavelengths are refracted more than lower- ultraviolet would bend more than infrared.
Reply:yes, all electromagnetic waves travel at the same speed in vaccum i.e 3*10^8m/s
Reply:In a vacuum, yes; otherwise, no.





I can't be bothered to set all the thumbs-down these answers deserve, but thank goodness for supastremph with a properly thought-out answer.
Reply:they all travel at the same speed, which is the speed of light..(3.5 x 10^8m)
Reply:In vacuum, all light travels at c. In different media, the group velocity of the wavefront is dependent on frequency. This is due to the relation v=c/n(f) where v is the velocity of the wavefront, c the speed of light in vacuum, and n(f) is the index of refraction for that frequency. For example red light signals travel faster through glass that blue.