forms of electromagnetic waves powerpoint

EM Waves

1. SCIENCE 10 Quarter 2 Week 1

2. LET’S DISCOVER

3. ELECTROMAGNETIC WAVES

4. OBJECTIVE/S: Compare the relative wavelengths of different forms of electromagnetic waves ( S10FE-IIa-b-47); Subtask: 1 .Identify the relationship among wavelength, frequency and energy of an electromagnetic wave. 2. Determine the different forms of EM waves. 3. Cite situations that applies EM waves.

5. DIFFERENT FORMS OF ELECTROMAGNETIC RADIATION

6. ELECTROMAGNETIC WAVES are waves which can travel through the vacuum of outer space . are formed when an electric field couples with a magnetic field. The magnetic and electric fields of an electromagnetic waves are perpendicular to each other and to the direction of waves.”

7. What is the speed of EM waves? • EM waves travel at the speed which is constant in a given medium and has a value of c=3.0 x 10 m/s in vacuum. •EM waves usually travel slowest in solids and fastest in gases 8

8. Cont. the wave speed, frequency, and wavelength are related by the following equation: v= ƛf Where; v is the wave speed or c (speed of light) is expressed in meters per second f for frequency which is expressed in Hertz ƛ for wavelength expressed in meters

9. EXAMPLE PROBLEMS: (Assume that the waves propagate in a vacuum) What is the frequency of radio waves with wavelength of 20 m? Given: v = c= 3 x 10 m/s f=? ƛ = 20 m Equation: v=c= ƛf f = c/ƛ Solution: f = c/ƛ = 3x10 m/s 20 m = 1.5 x 10 Hz 8 8 7

10. 2. What is the frequency of light waves with wavelength of 5 x10 m? Given: v = c = 3 x 10 m/s f=? ƛ = 5 x10 m Equation: v=c= ƛf f = c/ƛ Solution: f = c/ƛ f = ? -7 8 -7

11. 2. What is the frequency of light waves with wavelength of 5 x10 m? Given: v = c = 3 x 10 m/s f=? ƛ = 5 x10 m Equation: v=c= ƛf f = c/ƛ Solution: f = c/ƛ = 3x10 m/s 5x10 m = 6 x10 Hz -7 8 8 -7 -7 14

12. RADIATION is an energy that comes from a source and travels through space and may be able to penetrate various materials

13. Electromagnetic R adiation is a radiant energy coming from the sun. It is one of energies present in the universe . This energy is produced through nuclear reactions in the sun’s core which streams from its surface in waves of different wavelength. The shortest and the longest wavelength are invisible to the eye but medium wavelength is visible radiation we call sunlight. All substances give off electromagnetic radiation in the form of electromagnetic waves .

14. PIONEERING SCIENTIST James Clerk Maxwell formulated the Electromagnetic Wave Theory which says that an oscillating electric current should be capable of radiating energy in the form of electromagnetic waves. Heinrich Hertz - discovered the Hertzian waves which is now known as radio waves .

15. TYPES OF EM WAVES Radio waves Microwaves Infrared waves Visible light Ultraviolet X-rays Gamma rays

16. ACTIVITY

17. KEY CONCEPT Wavelength is the distance between crest to crest or trough to trough. EM waves are bounded at different ranges. Meaning each type of EM waves has upper and lower limits on the spectrum.

18. Directions : Using the illustration on the next slide, determine the wavelength ranges of each of the forms of electromagnetic waves. On a separate sheet of paper, copy and answer the given table. Afterwards answer the questions that follow.

19. Study the illustration below

20. Processing Questions : Q1.Which electromagnetic wave has the longest wavelength ? Q2.Which electromagnetic wave has the shortest wavelength? Q3.Observe what happens to the wavelength of the electromagnetic waves as they progress (goes rightward from the figure). Does the wavelength of the EM waves increase or decrease as we go from radio wave to gamma ray?

21. The Electromagnetic Spectrum

22. Table showing the EM waves’ wavelengths, frequencies, and energies

23. 1.Radio waves have the longest wavelength p roduced by making electrons vibrate in an antenna. u sed to transmit sound and picture information over long distances.

24. 2.Microwaves have smaller wavelengths than radio waves c an penetrate the atmosphere of the Earth used in satellite communication,radar,television transmission and cooking

25. 3.Infrared waves l ies beyond the red end of the visible light. i t is emitted by all objects. The amount and wavelength of radiation depend on temperature. Below 500 ͦ C , an object emits only infrared radiation. Above 500 ͦ C, an object glows and emits both infrared and some visible light.

26. 4.Visible Light When white light passes through a prism , it is separated into its constituent colors: - These colors do not distinctly separate but they continuously change from red to violet. Red has the longest wavelength from among these colors and violet has the shortest. R O Y G B I V

27. 5.Ultraviolet radiation l ies just beyond the violet end of the visible spectrum. h ave shorter wavelengths than the visible light and carry more energy. the SUN is the main source of UV radiation but there are also artificial sources of UV light.

28. 6.X - rays c ome just after the UV rays. t hey are of shorter wavelength but carries higher energy than the UV. X-rays are produced using an X-ray tube. They are emitted when fast moving electrons hit a metal target.

29. 7.Gamma rays l ie at the other end of the EM spectrum. t hey are shortest in wavelength and highest in frequency. they carry the highest amount of energy,thus they are more dangerous. emitted by stars and some radioactive substances.