How is the color of a material relate to its absorption and reflection of radiant energy?
The light waves you are talking about fall within the visible part of the electromagnetic spectrum. These are the light colors we can see. You can remember the order of these light colors by using the acronym ROY G. BIV, like it is sonebody's name. The colors are: red, orange, yellow, green, blue, indigo, and violet.
The combination of all these visible light colors is present in radiant energy from the sun. We call this mixture "white light". If you take a prism, you can break white light down into the constituent colors that make it up. This is what happens when there is a rainbow, sunlight gets broken down into its basic colors by all the raindrops acting like little prisms.
Basically, white objects are a combination of all these colors, so they reflect all the colors, so there is little absorption. That is why you would want to wear light colored clothing on a hot day, to absorb as little radiation as possible. Black, or dark colors, on the other hand, are the absence of any of the visible light colors, so they are all absorbed, which translates to high absorption and warmer temperatures. That is why you wear dark clothing on a cold day, to absorb and retain more radiation from the sun.