Wave and Optics: Infrared Radiation: Infrared radiation (IR) or infrared light

After successfully completing this lesson,
you should be able to:

1. Differentiate infrared from the other
types of electromagnetic spectrum

2. Explain the differences among five
regions of Infrared based on its Wavelength.

3. Identify the major characteristics of
Infrared; and,

4. Realize the importance of infrared
in industries and Astronomy.

1. WAVE AND OPTICS : I N F R A R ED Prepared by: Aljhey Laylay Malimata

2. Learning Objectives After successfully completing this lesson, you should be able to: 1. Differentiate infrared from the other types of electromagnetic spectrum 2. Explain the differences among five regions of Infrared based on its Wavelength. 3. Identify the major characteristics of Infrared; and, 4. Realize the importance of infrared in industries and Astronomy.

3. What is INFRARED? - Infrared radiation (IR) or infrared light, is a type of radiant energy that's invisible to human eyes but that we can feel as heat

4. - IR is a type of electromagnetic radiation that lies between visible light and radio waves. What is INFRARED? Figure 1. The Electromagnetic Spectrum - Wavelength range from about 700 nanometer (nm) to 1 millimeter (mm).

5. What are the two (2) major sources of INFRARED ? 1. Sun 2. Fire

6. • The amount of thermal or infrared radiation emitted by an object depends on its surface temperature, area, and characteristics. • The warmer objects emits more infrared than cooler one. IN FRA RED RA DI ATI ON

7. Differences between INFRARED and other types of Electromagnetic Spectrum • In terms of wave - Infrared waves are longer than those of visible light, but shorter than those of radio waves. • In terms of frequencies - IR are higher than those microwaves,but lower than those of visible light, ranging from about 300 GHz to 400 THz.

8. What are the Five Regions of INFRARED based on its wavelength . 1. Near Infrared 2. Short Wavelength Infrared 3. Medium Infrared 4. Long Wavelength Infrared 5. Far Infrared Figure 2. Regions of Infrared

9. Five Regions of INFRARED 1. Near Infrared - from 0.75 to 1.4 micrometres. Use in the medical field. 2. Short Wavelength Infrared - from 1.4 to 3 micrometres. 3. Medium Infrared - from 3 to 8 micrometres. 4. Long Wavelength Infrared - from 8 to 15 micrometres. 5. Far Infrared - from 15 to 1000 micrometres

10. DIS CO VE RIE S OF IN FR AR ED

11. Who discovered IN FR AR ED ? How he discovered it?

12. Sir William Herschel He did a simple experiment in which he dispersed sunlight through prism and placed a thermometer at the location of each colour . He noticed that the thermometer temperature increased.

13. Sir William Herschel Herschel's Experiment Then, he also placed the thermometer past red-end of the spectrum where there was no visible sunlight, the thermometer temperature's still increased.

14. Characteristics of INFRARED ORIGIN - from an alteration of electron movements. WAVELENGTH- 700 nm - 1mm FREQUENCY - 430 THz to 300 GHz TYPES OF WAVES- Transverse Wave

15. Characteristics of INFRARED SPEED - 3 x 10^8 m/s Does infrared a wave or Particle? According to quantum theory, infrared waves can exist as either wave or as a particle at the same time. Infrared radiation can be the source of heat as they have thermal properties. When infrared radiation strikes the oxygen or nitrogen molecules, the radiation makes the molecules move faster as they gain more energy.

16. IN F RA RE D - Also referred to as heat or thermal waves or electromagnetic waves. -Sometimes infrared rays are used in applications where heat production is required like in infrared heaters or for therapeutic purposes where a patient requires physical therapy.

17. Do ANIMALS can see INFRARED .

18. Human eye can't see infrared light but some animals can do. When an adult female mosquito looks for blood, she uses her infrared seeing skills to find a warm blooded host to bite.

19. Fish such as goldfish, salmon, pirana, and cichlid can see infrared light. Salmon and some other fresh water fish have an enzyme that switches their visual systems to activate infrared seeing which helps them to navigate and hunt in musky waters.

20. Harmful effects of INFRARED Radiation

21. The human eye is very sensitive to all of the radiation in electromagnetic spectrum like infrared radiation especially if that radiation is in the high level of intensity. Prolonged exposure to IR radiation causes a gradual but irreversible opacity of the lens.

22. Other forms of damage to the eye from IR exposure include scotoma, which is a loss of vision due to the damage to the retina. Even low-level IR absorption can cause symptoms such as redness of the eye, swelling, or hemorrhaging.

23. APPLICATION OF INFRARED

24. APPLICATION OF INFRARED 1. Heat Source Medical uses : Infrared radiation finds application as a heating source. There are infrared saunas used to treat high blood pressure and rheumatoid arthritis. Infrared radiation is considered to be one of the safest methods of physiotherapy.

25. Manufacturing industries : Industries which concentrate on manufacturing processes such as forming of plastics, curing of coatings, plastic welding, etc., use infrared heaters in place of contact heating and convection ovens.

26. 2. Astronomy Astronomers use optical devices such as mirrors, solid-state digital detectors, lenses to study objects from space with the help of infrared waves.

27. 2. Massage Therapy Infrared rays are used for warming the skin and for relaxing the muscles. Infrared rays are preferred because of their penetration quality through the skin.

28. THANK Y O U ! !