powepoint peresntation on character of elctromagnetic radiation

1. ducation and
Extension.

2. Character of electromagnetic
radiation
– Electromagnetic radiation:- The radiation that has both electric and magnetic
field and travels in waves and it can vary in strength from low energy to high
energy.
electromagnetic radiation consist of radio waves, microwaves, infrared ,
visible light ,uv rays &x-rays.

4. Radio waves
– Radio waves are type of electromagnetic radiation with wavelength in the electromagnetic
spectrum longer than infrared light
– Radio waves have frequencies as high as 300 giga hertz to as low as 30 hertz.
– Radio waves are generated by artificially transmitters and recived by radio recivers using
antennas .since radio frequency radiation has both electric an magnetic component it is often
convenient to express the intensity of radiation field in terns of unit specific to each component
– The radio waves form many transmitter pass through the air simultaneously without interfering
each other.

5. – Like all electromagnetic waves, radio waves in vaccum travel at the speed of light and in the
earth’s atmosphere at close, but slightly lower speed.
– *Application*
– 1)for television and FM and AM radio broadcast
– 2)military communication
– 3)mobile communication
– 4)wirless computer network
Formula to calculate radio waves
Speed of wave=wavelength X frequency
Radio waves are electromagnetic waves &travel at 2.997 x 108 m/s

6. Microwawes
– Microwave is a form of electromagnetic radiation whith ranging from about 1m to one mm
corresponding to frequencies between 300hz to 300ghz.
– It work on the principal of conversion of electromagneti energy into thermal energy
– Electromagnetic energy refers to radiation (waves)comprising an electric field and magnetic
field ascillating perpendicular to each other.

7. History
– It was invented acciedently in 1945 by
Dr. Percy LeBaron Spencer
– During world war 2, two scientist made
The magnetorn a tube that produce microvaves.
– In 1967 the fistr countertop domestic oven
Was introduced
– The first microvae oven was priced at $2,ooo
to 3,000$

8. Application
– Reheate and to cook food
– Disinfect kitchen items
– Heating beauty products
– Rosting honey and de-crystalling honey

9. UV-Rays
– Ultraviolet radiation (UVR) covers a smaller part of the electromagnetic spectrum lying
between the violet end of visible light and x-Ray Region

10. – Uv –rays is a form of electromagnetic radiation with the wavelength from 10nm to 400nm (750
thz) shorter then that of visible light
– It is present in the sunlight, and constitutes about 10% of the total electromagnetic radiation
aoutput from the sun
– It is also produced by electric arc and specialized light such as mercury-vapour lamps, tanning
lamps and black light.
– Shorter-wave ultraviolet light damages DNA and seterilizes surfaces with which it comes in
contact.
– The lower wavelengths limit of human vision is conventionally taken as 400nm,so uv rays are
invisible to humans, although some people can perceive light at slightly shorter wavelength
than this,
– Insect, birds,and some other mammals can see near-UV

11. Application of UV-Rays
– Killing bacteria
– Creating fluorescent effect
– Curing inks and resins
– Phototherapy and suntanning

12. X-Rays
– The X-ray was discovered In 1895 by German
Physicist nemed Wilhelm Roentgen
– He found shadow of his bone on fluorescent screen
– X-rays are from of electromagnetic radiation similar
to visible light but with short wave length
– X-radiation, is a penetrating form of
high-energy electromagnetic radiation.
– Most x-rays have a wavelength ranging from 10 pico to 10 nano

13. – Properties:-
X-Ray carry photons enough energy to ionize atoms and disrupt the molecular
bonds. This make it a type of ionizing radiation
This ionizing property is used to kill the malignant cell by radiotherapy
It interact with matter in three main ways through photo-absorbtion,Compton
scattering and Rayleigh scattering. The strength of these interaction depend
on the energy of the x-ray and element composition of material
It is absorbed by solid/radio-opaque substance like bones &metals

14. USES
– Based on the energy of the radiation, X-rays have wide range of uses like in the medical field, industrial
work places, security purposes etc.
– Used in X-Ray scanner.
– X-Ray crystallography
– Industrial radiography and CT scanning
– X-Rays has an immenes role in the medical field- diagnostic as well as therapeutic

16. DIFFRACTION OF DOUBLE
SLIT
– Diffraction:- The bending of wave around an obstacle is called diffraction
– The double-slit experiment is a 19 th century investigation into properties of light
– This experiment is sometimes refers to as youngs experiment
– The experiment belongs to a general class of “double path” experiments, in which a wave is split into
two separate wave that later combine backe to single wave

17. Youngs Experiment

18. – Thomos young in 1801, demonstrated for this first time the phenomenon of interference of light. His arrangement in this
experiment sunlight was allowed to pass through pinhole of s .
– The light emerging from S was allowed to pass through pinhole S1 and S2 act as coherent sources. The two sets of
spherical waves emergin from S1 and S2 interfere with each other amd produce a symmetrical interference pattern of
varying intensity on the screen.
– Contiuous circular lines reprent crests and dotted circular lines reprent troughs of waves. At pont marked by (x) , crests
of one wave are superposed on crests of the other, or troughs of one wave are superposed on the troughs of other. Such
pont are therefore of maximum brightness
– At point marked by (o) , crests one of wave are superimposed on throughs of the other wave
– In Youngs double slit experiment, the pinhole S1 and S2 were replaced by narrow slits and sunlight by monochromatic
light. The number of lternate bright and dark fringes running parallel to the length of the slits wre observed on the
screen. Thers fringes are equal width and thery are called interference fringes or bands.

19. Importance
– It was the first successful experiment to show the interference of light waves
– From this experiment, it is possible to calculate wavelength of monochromatic light using
formula 𝝀=xd/D , where X is fringe width , d is distance between two slits and D is distance
between screen and source