Electromagnetic Waves.pdf

ELECTROMAGNETIC WAVES  OBJECTIVES 1. describe the nature and properties of electromagnetic waves 2. differentiate ionizing and non-ionizing radiation 3. use wave speed equation to calculate the frequency , wavelength , and speed of the wave VIDEO PRESENTATION: ELECTROMAGNETIC WAVES ...

ELECTROMAGNETIC WAVES  OBJECTIVES 1. describe the nature and properties of electromagnetic waves 2. differentiate ionizing and non-ionizing radiation 3. use wave speed equation to calculate the frequency , wavelength , and speed of the wave VIDEO PRESENTATION: ELECTROMAGNETIC WAVES  reallygreatsite.com MARIST INSPIRES LEARNING / EMPOWERING. TRANSFORMING. LEADING  GUIDE QUESTIONS: 1. How will you describe an electromagnetic wave? 2. Based on the video presentation, how will you describe the motion of electric field and magnetic field in an electromagnetic wave? 3. Can you give an example of a source that produces electromagnetic wave? THINK, GROUP, SHARE: ELECTROMAGNETIC WAVES Directions: Each group will be given 10 minutes to analyze the images assigned to them. They will share insights and personal ideas about the basic concepts related to the pictures. A set of questions will be provided and should be answered by the group as a guide before the presentation. GROUP 1  GUIDE TASK/QUESTIONS: 1. How is electromagnetic wave produced? 2. How will you describe the position of electric field magnetic field and direction of the wave? GROUP 2  GUIDE TASK/QUESTIONS: 1. How will you differentiate ionizing radiation from non ionizing radiation ? 2. Give and explain at least two sources of ionizing and non ionizing radiation. GROUP 3 GUIDE QUESTIONS: 1. Identify and explain the parts of the wave. GROUP 4 GUIDE QUESTIONS: 1. Do you think these materials conduct electricity ? Why or why not? 2.Give at least one example of dielectric and its uses?  CRITERIA 5 4 3 2 1 Accuracy All ideas are Most of the ideas Some of the ideas Few of the ideas are The output lacks accurate are accurate are accurate accurate accuracy All elements of Most of the Some of the Few of the elements The output lacks Organization the output are elements of the elements of the of the output are organization organized output are organized output are organized organized from from simple to from simple to from simple to simple to complex complex complex manner complex manner manner manner Teamwork All members Most of the Some of the Few of the members The group lacks show members show members show show cooperation teamwork cooperation cooperation during cooperation during during the during the the presentation the presentation presentation presentation PRESENTATION GROUP 1  GUIDE TASK/QUESTIONS: 1. How is electromagnetic wave produced? 2. How will you describe the position of electric field and magnetic field and direction of the wave?  ELECTROMAGNETIC WAVES It is a form of radiation that travels through space They are formed when an electric field couples with magnetic field  ELECTROMAGNETIC WAVES Magnetic field and electric field of an electromagnetic field are perpendicular to each other and to the direction of the wave It is a wave that can travel through empty space and through matter  ELECTROMAGNETIC WAVES It is produced by moving charges It behaves as a transverse wave It carry energy from one place to another (Electromagnetic Radiation/Radiant Energy)  ELECTROMAGNETIC WAVES It can travel through a vacuum or a material substance move through a vacuum at the same speed (speed of 𝟖 light, c = 3 x 𝟏𝟎 m/s It exhibits reflection, refraction, diffraction and interference  reallygreatsite.com MARIST INSPIRES LEARNING / EMPOWERING. TRANSFORMING. LEADING GROUP 2  GUIDE TASK/QUESTIONS: 1. How will you differentiate ionizing radiation from non ionizing radiation ? 2. Give and explain at least two sources of ionizing and non ionizing radiation.  RADIATION Radiation is an energy emitted from a body or source that is transmitted through an intervening medium or space and absorbed by another body. Transmission is in the form of waves but wave/particle duality under quantum physics. SOURCES OF RADIATION  NON-IONIZING VS IONIZING RADIATION Radiation is classified as being either non-ionizing or ionizing. Non-ionizing radiation is longer wavelength/lower frequency lower energy. While ionizing radiation is short wavelength/high frequency higher energy. GROUP 3 GUIDE QUESTIONS: 1. Identify and explain the parts of the wave.  WAVES These are disturbances propagating in a medium or in vacuum , carrying energy.  It is the highest part The distance maybe from crest the wave to another crest or trough to another trough It is the height of the wave It is the lowest part the wave  BASIC WAVE EQUATION Frequency (f) – it is the number of waves produced in a given amount of time SI unit is Hz means Hertz or (1/s) BASIC WAVE EQUATION Period (T)- It is the time for the source to produce one complete wave SI unit is s means seconds  BASIC WAVE EQUATION Wavelength ( λ ) – It is the distance between any two successive points The distance maybe from crest to another crest or trough to another trough SI unit is m or meters  BASIC WAVE EQUATION Speed of a wave (v) – It is the distance the wave travels per unit time SI unit is m/s or meter per second BASIC WAVE EQUATION Speed of the wave: v = λf v= speed of the wave λ = wavelength f= frequency BASIC WAVE EQUATION Wavelength λ = 𝑣/𝑓 v= speed of the wave λ = wavelength f= frequency BASIC WAVE EQUATION 𝑣 1 f= ,f= λ T v= speed of the wave λ = wavelength f= frequency T= period BASIC WAVE EQUATION Period T = 1/f f = frequency BASIC WAVE EQUATION Period T = 1/f f = frequency  G. R. E. S. A METHOD G – Given R- Required E- Equation S- Solution A- Answer SAMPLE PROBLEM 1. A radio wave is travelling at a speed 300,000,000 m/s. It has frequency of 4 1X10 Hz. Calculate the wavelength of the wave? SAMPLE PROBLEM 1. A radio wave is travelling at a speed 300,000,000 m/s. It has frequency of 4 1X10 Hz. Calculate the wavelength of the wave? GIVEN : v = 300,000,000 m/s 4 f= 1X10 Hz REQUIRED : λ=? EQUATION : λ = v/f SOLUTION : λ = v/f 4 λ = 300,000,000 m/s / 1X10 Hz ANSWER : λ = 30,000 m SAMPLE PROBLEM 2. A radioactive source produced a gamma radiation that has a wavelength −12 of 1x10 m. What is the frequency if 8 the speed of the wave is 3x10 m/s ? GIVEN : v = 300,000,000 m/s −12 λ= 1x10 m REQUIRED : f= ? EQUATION : 𝑣 f= λ SOLUTION : 𝑣 f= λ 300,000,000 m/s f= 1x10−12m ANSWER : 20 f = 3x10 Hz GROUP 4 GUIDE QUESTIONS: 1. Why do you think these materials cannot conduct electricity? 2. Give at least one example of dielectric and its uses.  DIELECTRIC Dielectric materials are poor conductors of electricity because they do not have any loosely bound or free electrons that may drift through the material. Air, glass, and pure water are nonconducting materials known as dielectrics.  WAVE SPEED THROUGH A DIELECTRIC 𝑐 v= 𝑘 where: v = wave velocity (m/s) c = speed of light (3 x 108 m/s) k = relative dielectric constant REFRACTION OF LIGHT The speed of light changes when it travels from one medium to another. The moment that a light ray leaves a certain medium and enters a new one, it refracts or it bends away from its original path. The index of refraction of a material is the ratio of the speed of light in a vacuum to the speed of light in the material.  Index of refraction can be computed using this equation; 𝑐 n= 𝑣 n = index of refraction c = speed of light in a vacuum v= speed of light in the material What is the index of refraction for the glass? GIVEN: c = 3 x 10 ⁸ m/s 𝑣𝑔𝑙𝑎𝑠𝑠 = 2.0 x 10 ⁸ m/s What is the index of refraction for the glass? REQUIRED: n=? What is the index of refraction for the glass? EQUATION: 𝑐 n= 𝑣 What is the index of refraction for the glass? SOLUTION : 𝑐 n= 𝑣 (3 x 10 ⁸ m/s) n= (2.0 x 10 ⁸m/s) n = 1.5 What is the index of refraction for the glass? ANSWER : n = 1.5 1. How will you describe the nature and properties of electromagnetic waves? 2. How will you differentiate ionizing and non-ionizing radiation? 3. How will you compute the motion of the electromagnetic wave in terms of : a. Wave speed d. index of refraction b. Frequency e. wave speed in dielectric c. Wavelength  OBJECTIVES describe the nature and properties of electromagnetic waves differentiate ionizing and non-ionizing radiation use wave speed equation to calculate the frequency , wavelength , and speed of the wave ELECTROMAGNETIC SPECTRUM OBJECTIVES 1. Discuss the electromagnetic spectrum 2. Calculate the energy of an electromagnetic wave 3. Explain the biological effects of electromagnetic radiation 3. Show the significance of electromagnetic waves in our daily lives THINK-PAIR-SHARE: EELECTROMAGNETIC SPECTRUM Directions: The class will find a pair for this activity. Using the image as a guide, each pair will compare the frequency, energy and wavelength of electromagnetic waves in the spectrum. After 10 minutes, selected pairs will present their answers to the class. GUIDE QUESTIONS: 1. What happens to wavelength of the wave when frequency increases? 2. How will you arranged the types of electromagnetic waves based on frequency? 3. What happens to the energy of the wave when wavelength increases? USES OF ELECTROMAGNETIC WAVES OTHER MATTERS  ELECTROMAGNETIC SPECTRUM Radio: Your radio captures radio waves emitted by radio stations, bringing your favorite tunes. Radio waves are also emitted by stars and gases in space. Microwave: Microwave radiation will cook your popcorn in just a few minutes, but is also used by astronomers to learn about the structure of nearby galaxies.  ELECTROMAGNETIC SPECTRUM Infrared: Night vision goggles pick up the infrared light emitted by our skin and objects with heat. In space, infrared light helps us map the dust between stars.  ELECTROMAGNETIC SPECTRUM Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible light. Ultraviolet: Ultraviolet radiation is emitted by the Sun and are the reason skin tans and burns. "Hot" objects in space emit UV radiation as well. ELECTROMAGNETIC SPECTRUM X-ray: A dentist uses X-rays to image your teeth, and airport security uses them to see through your bag. Hot gases in the Universe also emit X-rays. Gamma ray: Doctors use gamma-ray imaging to see inside your body. The biggest gamma-ray generator of all is the Universe.  ENERGY OF THE WAVE The energy of electromagnetic radiation is dependent on it’s frequency The higher the frequency, the greater the energy of radiation ENERGY OF THE WAVE Specifically, the energy (E) of a wave is related to it’s frequency (f) by the following equation : E= hf ENERGY OF THE WAVE E= energy of the wave h= is the Planck’s constant which is −34 equal to 6.63𝑥10 J. s f= frequency 8 c= 3.0 𝑥10 m/s SAMPLE PROBLEM 1. Calculate the energy of a wave 8 travelling with a speed of 3x10 m/s and −8 has a wavelength of 1x10 m. GIVEN : 8 v = 3 x10 m/s −8 λ= 1x10 m REQUIRED : f= ? E= ? SOLUTION: 𝑣 f= λ 3x m/s 108 f= 1x10−8 m ANSWER: 16 f = 3x10 Hz SOLUTION: E= ? E= hf −34 16 E= (6.63𝑥10 J. s)(3x10 Hz) −34 16 E= (6.63𝑥10 J. s)(3x10 1/s) ANSWER: −17 E= 1.99𝑥10 J SAMPLE PROBLEM 2. Calculate the energy of a photon of light that has a wavelength of 0.0005 m. GIVEN : 8 v = 3 x10 m/s λ= 0.0005 m −34 h= 6.63𝑥10 J. s REQUIRED : f= ? E= ?  EQUATION : E= hf SOLUTION : f= v/ λ 8 f= 3 x10 m/s/0.0005 m 11 f= 6 x10 Hz SOLUTION : f= v / λ 8 f= 3 x10 m/s/0.0005 m 11 f= 6 x10 Hz SOLUTION : E= hf −34 11 E= (6.63𝑥10 J. s)(6 x10 Hz) −22 E= 3.98𝑥10 ANSWER : 11 f= 6 x10 Hz −22 E= 3.98𝑥10 J PENETRATION OF ELECTROMAGNETIC WAVES IN THE LAYERS OF ATMOSPHERE USES AND EFFECTS OF DIFFERENT EM WAVES  RADIO WAVES DISCOVERER SOURCES USES EFFECTS Heinrich Hertz Oscillating Telecommuni Migraine Circuits cation Headache Stars RADAR Harm Body Sun Broadcasting Cells WIFI GADGET FOR DETECTION: earphones, diodes, aerial antennae  MICRO WAVES DISCOVERER SOURCES USES EFFECTS James Clerk Oscillating RADAR Internal Maxwell Circuits Cooking heating of Communicati body tissue on Satellites Cataract GADGET FOR DETECTION: satellite dishes  INFRARED DISCOVERER SOURCES USES EFFECTS William Sun Night vision Sunburn Herschel Devices equipment Overheating used in Thermography heating cooking Remote controls GADGET FOR DETECTION: blackened bulb, thermometer, thermopile, phototransistor  VISIBLE LIGHT DISCOVERER SOURCES USES EFFECTS Roger Sun Vision Eye health Bacon Laser Photosynthesis problems Isaac Incandescent Photography objects Newton GADGET FOR DETECTION: photo film and photoelectric cell  ULTRAVIOLET DISCOVERER SOURCES USES EFFECTS John Sun Sterilization of Skin cancer Wilhelm Electric medical equipment blindness Ritter Sparks Discharge kill sunburn tube microorganisms Mercury Helps production Vapor Lamp of vitamin D GADGET FOR DETECTION: fluorescence and photographic film  X-RAYS DISCOVERER SOURCES USES EFFECTS Wilhelm X-ray tube Radio therapy May damage Conrad Stars Radiography central Roentgen nervous system Damage cells GADGET FOR DETECTION: photographic film  GAMMA RAYS DISCOVERER SOURCES USES EFFECTS Paul Villard Cobalt-60 Sterilization of Cause Cesium- 137 medical instruments cancer Radio therapy Genetic Detects crack in Mutation metals Death GADGET FOR DETECTION: Geiger Muller Tube , Photo film, Radiation Detectors IPC 1.3 Detecting Electromagnetic Waves Identify five objects or technologies in the image corresponding to specific electromagnetic wave types. For each identified wave, briefly explain its context or application as shown in the image. IPC 1.3 Detecting Electromagnetic Waves For example, if the image shows a microwave oven, describe how it uses microwaves to heat food. If there is a camera, explain how it utilizes visible light to capture images. Also, refer to the Rubric for "Detecting Electromagnetic Waves" 1. How will you explain the relationship of wavelength, energy and frequency of electromagnetic wave? 2. Why do you think electromagnetic waves are useful in our every day lives? 3.How will you protect yourself and our environment from the exposure of harmful electromagnetic radiation? OBJECTIVES Discuss the electromagnetic spectrum Calculate the energy of an electromagnetic wave Explain the biological effects of electromagnetic radiation Show the significance of electromagnetic waves in our daily lives