Showing posts with label infrared radiation. Show all posts
Showing posts with label infrared radiation. Show all posts

Wednesday, 13 March 2019

The insider's guide to ELECTROMAGNETIC SPECTRUM

You gonna find out in-depth knowledge of electromagnetic spectrum, electromagnetic spectrum wavelengths and many such answers to your query in this post the insider's guide to the electromagnetic spectrum.

ELECTROMAGNETIC SPECTRUM

The electromagnetic spectrum is a depiction of every electromagnetic wave and their related wavelengths, for that one must know about electromagnetic waves 


what is electromagnetic wave ??

The electromagnetic wave is a huge term, it consists of many categories named gamma rays, x rays, ultraviolet, infrared, visible, microwave, radio rays.

you must be familiar with many of the above-mentioned terms such as X-RAY, microwave, and radio.

electomagnetic spectrum


from a light bulb to mobile phone waves, from X-ray machine waves to microwave oven waves all are electromagnetic waves

electromagnetic waves are basically the form of energy, they have electric and magnetic fields associated with them so they are termed as electromagnetic waves

light from the sun comes down on earth in the form of gamma rays, x rays, ultraviolet and in almost every category 

WHO DISCOVERED ELECTROMAGNETIC SPECTRUM??

For most  history, there was belief visible light was only part of the electromagnetic spectrum, the ancient Greeks identified that light travels in the straight line and also identified some of its properties the study of the light continued between 16th and 17th century 

there was a conflict whether light is wave or particle form, the first discovery of electromagnetic radiation came from William harshel when he discovered the infrared light

the next year john ritter working on other hand found out ultraviolet rays, electromagnetic radiation was first linked to electromagnetism when ferrade first found out deflection in waves due to the presence of the magnetic field

during 1860 Maxwell developed partial differential equations of an electromagnetic field, he identified that electromagnetic waves have infinite wavelengths with all traveling at speed of light thus there was a consensus that light is a type of electromagnetic wave

in an attempt of solving  Maxwell's equations and check such low-frequency electromagnetic radiation, Henrich Hertz built an set up to generate and detect what now are called radio waves

hertz focused the waves using the lens made of tree resin and hertz similarly produced and measured properties of the electromagnetic wave, Wilhelm Longton noticed a new type of radiation emitted during an experiment with an evacuated tube subjected to high voltage

he called it X rays, in 1900 last portion of gamma rays was discovered by Paul Villard, in 1910 Henry Bragg identified gamma rays as electromagnetic radiation

ELECTROMAGNETIC SPECTRUM WAVELENGTHS

Electromagnetic waves are  described by any of the following properties namely frequency, wavelength or photon energy .frequncy of spectrum varies from  2.4×1023 Hz  
of gamma rays to 1 kHz of the ionized plasma state

wavelengths are inversely proportional to frequency, a wavelength of gamma rays is very short on the other hand it can be very long almost as long as the universe 

photon energy is directly proportional to frequency so gamma rays having the highest photon energy and radio waves have the lowest photon energy 


above equations show the relationship between energy, wavelength, and speed of light 

c is a speed of light in vacuum and h is constant of a plank.

now let's look at the types of waves in detail,



Gamma radiation


gamma radiation is penetrating radiation arises from a decay of nuclei of an atom, Rutherford named it gamma rays due to its relatively higher penetration of the matter 

gamma rays are in energy from few Kev to 8 MeV, some gamma rays of the ranges 100 to 1000 Tev are observed coming from the quasar 


electromagnetic spectrum


natural resources of this radiation earth are a result of radioactive decay and secondary radiation comes from atmospheric interaction with cosmic particles some other resources are nuclear fission which shown in the nuclear reactor

some other are nuclear fusion and nuclear fusion reactor, gamma rays, and x rays are both electromagnetic waves and they overlap in spectrum 

however they are distinct by their origin unlike gamma rays, an origin of x rays are outside nuclei

this is the most energetic photons having no least defined wavelengths, it is having the highest frequency among all, in astronomy, they are important for studying high energy objects or regions

gamma rays are used highly in experiments by scientists for their penetrating ability and produced by the number of high radioisotopes

they are used for irradiation of food and seeds for sterilization and in medication, they are used for cancer therapy, gamma rays are used for diagnostic imagining in nuclear medicine

the wavelengths of gamma rays can be measured by Compton scattering

gamma rays are ionizing radiation and are biologically hazardous, due to high penetrating capacity they can damage bone marrow and internal organs, thereby posing a challenge of safeguarding our body

and require shielding made by lead or concrete



X RAYS

It is also ionizing and due to its high energy it can also interact with matter through Compton effect  hard X rays have shorter wavelengths then soft X rays 

as they can pass through an object without being absorbed, such as they can pass through a thickness of less than several meters of water, they are used in diagnosis in a medical field in astronomy the accretion disks around neutron stars and black holes  

ULTRAVIOLET RADIATION

It designates a band of the electromagnetic spectrum with wavelengths from 10 nm to 400 nm, it contributes about 10 percent of the sunlight power

the biological and chemical effects of UV are greater than simple heating effects, suntan and sunburn are major effects of interaction of skin and UV rays
Known as a UV ray they are longest in wavelengths, whose photons are energetic enough to ionize atoms, too much exposure to UV rays can damage living tissue, UV can also cause some objects to glow in visible light which is called fluorescence

electromgnetic spectrum


middle range UV rays can cause damage to DNA of cells and therefore responsible for skin cancer thereby putting in danger the longevity of the one, human beings, and many other organisms could have harmed a lot if the earth has been not filtering them

sun also emits hazardous UV rays, however, long wavelength and short wavelength UV rays are absorbed by nitrogen and oxygen in the atmosphere and middle ranged UV rays are absorbed by the ozone layer to some extent.

VISIBLE RADIATION 

Above infrared in frequency comes visible light, the sun emits its maximum power through these rays, however integrating all wavelengths shows that max power is slightly higher than infrared 

the human eye is most sensitive to these waves that is the reason these rays are visible through human eyes, rainbow shows the different shades of visible light with infrared falls just below red

and UV falls just higher than the violet, visible light has a wavelength between 380 nm to 760 nm 

INFRARED RADIATION

Infrared section of waves covers the frequencies between 300 Mhz to 400 Thz., there are three categories in it 

FAR INFRARED - From 300 GHz to 30 THz, the lower part of these  waves can also be called microwaves, waves of this range is absorbed by water in the atmosphere making it opaque

MID INFRARED - From 30 THz to 120 THz, hot objects can radiate strongly in this range, the human body radiates strongly at the lower region of this category

NEAR INFRARED - From 120 THz to 400 THz, physical processes which are relevant to this range is similar to that of the visible light, highest waves in this range can be identified by photographic films directly 

the balance between the radiated infrared and absorbed rays have a critical impact on earth's climate, infrared radiation is emitted, infrared radiation is used in industrial, scientific, military, law enforcement and medical field

it is also used in night vision devices which allows a user to observe human or animals without being detected.

TERAHERTZ RADIATION

This range is in between microwave and infrared until recently this was not identified, the range was rarely studied and few sources existed for the microwave energy at the high end of the band 

but applications such as imaging and communicating are now appearing scientist are also now looking to apply this technology in armed forces.

MICROWAVES 

They are waves with short wavelengths, from 10 centimeters to 1 millimeter in the SHF and EHF frequency ranges, they are absorbed by antennas, they are also absorbed by polar molecules

unlike light and infrared rays, microwaves penetrate deep down and are absorbed through surfaces, this effect is used in microwave ovens to cook and also in industrial heating

Image result for microwave radiation

 RADIO FREQUENCY

Radio waves are emitted and received by antennas, which consists of conductors such as resonators, in a generator of radio waves transmitter generates AC current which is applied to the antenna,

the oscillating electrons in an antenna generate electric and magnetic fields which radiates away as radio waves, radio waves are widely used to transmit information across distances in radio communication systems

they are used in radio, television, two-way radio, satellite communication, this waves are received by the receiver and demodulated to get the information, a range of wavelength is 10 m to 100000 km.