Salam (May God Bless You). Today I have brought to you the article based upon the electromagnetic spectrum which consists of a 7 transverse waves. I will also briefly describe the applications of the waves known to be in the electromagnetic spectrum.

The Visible Light Spectrum

In 1686, Sir Isaac Newton placed a prism shaped glass block in front of sun light and determined that he could see almost 7 different colors.

If we observe, then the light coming from the sun or a lamp is a white light. This white light tends to disperse into the 7 different colors.rainbow colors.jpg

This dispersion is due to refraction of the light. Why this happens is because the white light is an electromagnetic wave and thus have the property of a wave, it seems to have various wavelengths.

Because of having different wavelengths, each wave refracts at different rates, this causes the beam of light to seperate into 7 separate beams of light.

In a rectangular glass block the light beams tend to refract back together when it exits the block but the geometry of a prism causes the light beams to refract more.

The red light refracts the least while the voilet ray of light refracts the most compared to other light beams.

A point to note is that there is no gap or a clear boundry between these rays of light which is why this is called a continuous spectrum.

You should know that the red light has a longer wavelength while the voilet light has the smallest wavelength compared to others.

These waves travel at the same speed in air and in a vacuume; 300 000 000 m/s, which is called the speed of light.

Since the speed is always the same, the increase in wavelength causes a decrease in frequency. The decrease in wavelngth causes an increase in frequency. rainbow colors wavelength.jpg

These wavelengths are so small that we use the term nanometer to measure the wavelengths of the waves. Fun Fact is that humans can only see 400 to 700 nm wavelengthsand those who cannot differentiate between these wavelengths are called colorblind.

To test this we use the equation mentioned in previous articles; v = fλ. You will notice the result as you calculate.

Electromagnetic Spectrum

The electromagnetic spectrum consists of the electromagnetic waves which are transverse waves.

These are emitted by the sun. Part of these series are; Gamma rays, X-rays, Ultra-voilet, Visible Light, Infra-red, Microwaves, Radiowaves.

electromagnetic spectrumThe rays of light are also in a continuous spectrum as in the case of visible light. The Gamma ray has the shortest wavelength but the highest frequency while the radiowaves have the longest wavelength but have shortest frequency.

These waves also travel at the same speed, the speed of light.

The energy each wave can transfer depends upon the wavelength and the frequency of the wave. A short wavelength can transfer more energy than those with a longer wavelength and a wave with higher frequency can transfer more energy while the waves with shorter frequency cannot transfer much energy.

The Gamma Rays can transfer more energy than any other wave in the spectrum while the radio waves transfer far less energy.

The word Ultra-voilet means “beyond voilet” meaning that the frequency of the waves on this side is higher than the voilet ray of light in the visible light. Infra-red means “below red” meaning that the frequency of these waves are lower than red.

Applications of The Electromagnetic spectrum

The electromagnetic spectrum has proved its uses over the years.gamma ray image of body

Gamma rays are emitted by the decay of radioactive nuclei. It is useful mainly in the medicinal sector, where these waves are used for different purposes. One of which is that the rays are used to make pictures or diagrams of organs because it penetrates the skin easily and can be detected. It is also used to treat cancer. These rays are very dangerous to living tissue which makes them excellent for killing cancerous cells. These rays are also used to detect cracks in metals of a building or an object where it is impossible to do so.

bone-xray-hands.jpgThe X rays are also used in the medicinal sectore, these are also capable to penetrate human skin but are stopped at the bones which are much harder than human flesh. This is useful to make Xray diagrams of bones to detect injury.

The Ultra voilet rays are very harmful to living tissue. Most of it is reflected off the Earth’s Surface, but our bodies have a further protection in our skin. Our skin has a pigment called melanin which gives our skin its color. It absorbs the Ultravoilet rays and do not let them enter the flesh. The Ultra voilet rays are used in SunBeds to tan our skin, the waves causes our skin tosun bed.jpg produce more melanin.

Visible Light is very useful today, it is the very source of light in the darkness of night time and is also used in fiber optics to transfer large bits of data around.

The infra-red are rays emitted by a hot object. The hotter an object the more infra-red rays it will emit. These rays have small range infra red remote.gifof wavelengths and frequencies. It is used in many household applications such as alarm detectors which detect a change in heat energy which is detected by these rays. These rays are also used by your t.v remote which sends signals to the t.v, each button has its own frequency and a little difference in wavelength in the infra-red waves. satellite.jpg

The Microwaves are not reflected or absorbed by the Earth’s atmosphere. This makes it useful for sending signals across the space, and to the sattelites.

cell tower.jpgRadio waves are reflected by the Earth’s atmosphere, this is why these are used in communications. The waves can travel over the horizon, to large distances making it useful for contacting someone across the country.


With this I end this Article.

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