Light is a wave of vibrating electric and magnetic fields. It is one small part of a larger range of vibrating electromagnetic fields. This range is called the electromagnetic spectrum. This is called the speed of light. The energy of the radiation depends on its wavelength and frequency.
Frequency is the number of waves that pass by each second.
The longer the wavelength of the light, the lower the frequency, and the less energy it contains. Light from the sun or a light bulb may look white, but it is actually a combination of many colors. We can see the different colors of the spectrum by splitting the light with a prism. The spectrum is also visible when you see a rainbow in the sky. The colors blend continuously into one another.