Slide 1

Waves

4th Year

Rowena D. Olicia
CTP-LEAP
Philippines


Slide 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.


Slide 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



Slide 4

Parts of Waves

Wavelength 
wavelength
Amplitude A

wave crest

distance

amplitude
wave trough
time


Slide 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



Slide 6

Wave Characteristics


Slide 7

Characteristics of Waves
Frequency f (inverse of period T) number of cycles per
second (Hertz)
T

f=c/
T=1/f


Slide 8

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


Slide 9

EM Spectrum

www.andor.com/


Slide 10

Amplitude
Maximum displacement from
the equilibrium (midpoint)
position


Measure of how much energy
the wave has




Slide 11

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


Slide 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 = λf



Slide 13

Sample Problems
1)

2)

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


Slide 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


Slide 15

2) Given:

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


Slide 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


Slide 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)


Slide 18


Slide 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/