1. Waves Rowena D. Olicia CTP-LEAPPhilippines 4 th Year

2. TARGETS At the end of the lesson, 75% of the students should be able to:  Define waves.  Identify the characteristics of wave.  Solve problems on waves.

3. WAVES  are disturbances that propagate through space  are also called energy carriers  transfer energy from one point to another  do not carry the particle of matter  only cause particle of matter to vibrate / move back and forth

4. Parts of Waves Wavelength Amplitude A distance time wave crest wave trough wavelength amplitude

5. Examples of Waves  Water surface waves  Sound  Electromagnetic Waves (EM Waves) - radio/TV waves, microwave, infrared, visible light, ultraviolet, X-rays, gamma  Seismic waves

6. Wave Characteristics

7. Characteristics of Waves Frequency f (inverse of period T) number of cycles per second (Hertz) f = c / T = 1 / f T

8. Wavelength ( λ ) Wavelength ( λ )  distance between successive identical parts of a wave  distance the wave has traveled in one complete cycle

9. EM Spectrum www.andor.com/

10. Amplitude  Maximum displacement from the equilibrium (midpoint) position  Measure of how much energy the wave has

11. Frequency (f)  number of waves that pass a given point per unit of time Unit: hertz (Hz)

12. Period (T)  time for a wave to complete a cycle  reciprocal of frequency  T= 1/f Wave Speed (v)  speed with which waves pass a particular point  Wave speed = wavelength / period  v = λ / T or v = λ f

13. Sample Problems 1) A vibration of frequency 5Hz sends a wave of 0.8m down a rope. What is the speed of the wave? 2) A wave of wavelength 1.5m travels down a rope at a speed of 6m/s. What is the frequency of the wave?

14. Solutions 1) Given: frequency (f) = 5Hz wavelength ( λ ) =0.8m speed (v) =? Formula:V =f x V = 5 Hz x 0.8m V = 4.0 m/s

15. 2) Given: velocity (v) = 6m/s wavelength( λ )= 1.5m frequency (f) = ? Formula: f= v/ f= 6m/s 1.5m f= 4Hz

16. SUMMARY I. Waves  disturbances in space/matter  energy carriers II. Kinds  Mechanical Waves (need a medium) a. longitudinal (propagation parallel to motion) ex. sound b. transverse (propagation perpendicular to motion) ex. String wave  EM Waves (do not need a medium) ex. Radio/TV waves, microwave, visible light, UV, X-rays

17. SUMMARY III. Wave Characteristics  Wavelength (crest-crest; trough-trough)  Frequency (no. of waves per second)  Amplitude (maximum displacement)  Period (time to complete one cycle)  Wave speed(wavelength over period)

19. REFERENCES http://hyperphysics.phy-astr.gsu.edu/hbase/sound/tralon.html sol.sci.uop.edu/.../chapter10/refraction.jpg www.gcsescience.com/Transverse-Wave.gif http://dev.physicslab.org/ http://www.physicsclassroom.com/Class/waves/U10L3c.html www.fen.upc.edu/