T1L8 - Quantifying Electromagnetic Waves (1).pdf

QUESTION OF THE DAY... What is light? DUAL NATURE OF LIGHT Sometimes it behaves like a particle (known as photon) Sometimes light behaves as the wave  GOAL determine the wavelength and frequency of various e...

QUESTION OF THE DAY... What is light? DUAL NATURE OF LIGHT Sometimes it behaves like a particle (known as photon) Sometimes light behaves as the wave  GOAL determine the wavelength and frequency of various electromagnetic waves  Quantifying ELECTROMAGNETIC WAVES Electromagnetic Waves formed when an electric field comes in contact with a magnetic field. The electric field and magnetic field are perpendicular (at right angles) to each other. Wave Anatomy  Wave Anatomy A B D F A G C E  Wave Anatomy Equilibrium Position Crest Wave Height Amplitude Node Trough Wave Length  W A V E S -a periodic disturbance in a medium or in space and carries energy with it  W A V E S TYPES (according to transmission): 1. Mechanical Waves 2. Electromagnetic Waves Mechanical Waves not capable of transmitting energy through a vacuum Require a medium Mechanical Waves EXAMPLES Electromagnetic Waves can transmit energy through vacuum do not require a medium to propagate SPEED in vacuum: 3 x 10^8 m/s Electromagnetic Waves EXAMPLES Electromagnetic Waves TYPES Quantifiable Properties of Waves Wave Speed (v) - the distance a wave travels in a given unit of time UNIT: m/s Wave Length (λ) - the distance between successive points of equal phase in a wave (crest to crest, trough to trough) UNIT: m  Propiedades Quantifiable Cuantificables de Properties of Waves las Ondas  Propiedades Quantifiable Cuantificables de Properties of Waves las Ondas WAVELENGTH Meters  Propiedades Quantifiable Cuantificables de Properties of Waves las Ondas WAVE SPEED Quantifiable Properties of Waves Wave Frequency (f) - number of waves passing a point in a given time. UNIT: hertz (cycle/sec) Period (T) - time it takes for one wave (one cycle) to pass a given point UNIT: s (seconds/cycle) Quantifiable Properties of Waves 1 cycle Quantifiable FREQUENCY Properties of Waves GIVEN TIME 1 seconds Quantifiable Properties of Waves FREQUENCY Which has higher frequency value? Quantifiable PERIOD Properties of Waves One Cycle: How long? Wave Speed Equation v = wave speed (m/s) λ = “lambda” - wavelength (m) f = frequency (Hz)  SAMPLE PROBLEM 1 An EM wave has a frequency of 1000Hz. What is the wavelength of this wave?  SAMPLE PROBLEM 2 An EM wave has a wavelength of 80nm. What is the frequency of this wave? BOARD WORK  BOARD WORK 1 A wave has frequency of 50 Hz and a wavelength of 10 m. What is the speed of the wave?  BOARD WORK 2 A wave has frequency of 5 Hz and a speed of 25 m/s. What is the wavelength of the wave?  BOARD WORK 3 A wave has wavelength of 10 m and a speed of 340 m/s. What is the frequency of the wave?  BOARD WORK 4 Radio waves travel at a speed of 300,000,000 m/s. WFNX broadcasts radio waves at a frequency of 101,700,000 Hertz. What is the wavelength of WFNX’s radio waves?  BOARD WORK 5 The speed of a wave is 65 m/s. If the wavelength of the wave is 0.8 meters, what is the frequency of the wave?  Generalization A wave is a periodic disturbance in a medium or in space and carries energy with it. Two main types of waves according to transmission are: _________ and ________ The value of speed of EM waves is ______ Quantifiable properties of waves can be solved through _________________. Lesson Complete! Congrats!