For years, electricity and magnetism was believed to be two separate forces till Scottish physicist, James Clerk Maxwell developed the theory of electromagnetism in 1873. This is Now You Know and let's find out about the electromagnetic spectrum today.

Light is nothing but a wave of alternating electric and magnetic fields. Most of the light in the universe is invisible and the electromagnetic spectrum is the term scientists use to describe the entire range of light that exists. Let's list the 7 regions the spectrum is divided into with increasing frequency and energy.

1. Radio waves - they are the lowest range of the spectrum with frequencies upto 30 Gigahertz. We use them for voice, data and entertainment media communications.

2. Microwaves - they have frequencies between 3 Gigahertz and 30 Terahertz. We use them for high-bandwidth communications and for generating heat for many industrial applications. You guessed it right, they also cook our food in our microwave ovens.

3. Infrared - We use them in thermal imaging cameras, TV or air conditioner remote controllers, and fiber optic cables too which help us connect to the Internet.

4. Visible light - this is the range of wavelengths that most human eyes can see. Hard to believe but this is actually the smallest portion of the electromagnetic spectrum.

5. Ultraviolet light - it's a component of sunlight but human eyes can't perceive this. It has several applications in the medical industry but overexposure can damage living tissues. Now you know why sunglasses with UV-guard and sunscreen lotions are expensive, don't you?

6. X-rays - they are produced by accelerating electrons. We use them for checking bone fractures and detecting breast cancer. It helps us in checking the severity of pneumonia as well.

7. Gamma rays - they are produced by atomic nuclei. Hard X-rays occupy the same region. Overexposure can be fatal to humans however, carefully measured doses to small regions have been proven to kill cancer cells.