University:
University of Colorado Boulder
Course:
PHYS 2020 | General Physics 2
Academic year:

2020
Views:

500

Pages:

2
Author:

Fecysymncreexf004

It h f LA if n $TtArr -o 0 V/ w , ? Name: Diffraction PhET Lab k - Introduction: When waves momentarily overlap, they temporarily add their amplitudes vs * x «r.'? without affecting the original waves. This interference can be seen when two wave sources are used and their overlaps viewed. You will view this phenomenon in parts I and II of this lab. When a wave strikes a barrier, some of the energy will bend around the barrier and spread out. This is known as diffraction . In part three of the lab, you will view the results of splitting a Wave Interference single wave source with a narrow slit, and then observe as the new waves created at the slit interfere. The interference pattern that results is symmetrical. The bands of constructive interference are referred to as maxima ( single-maximum ) . - Procedure: Go to https://connexions.github. io/ simulations/ wave interference/ Part 1: Water Waves Analogy take some time to familiarize yourself with the simulation' s controls Observe the water waves created in the faucet analogy. The darker areas are areas of higher amplitude. Adjust frequency and amplitude and observe the characteristics of the waves. Comment on the waves as amplitude is changed : j ft WnO so ( Comment on the waves as frequency is changed: Sfy\ a {\ c? r ) ^ L’fcl T " f5 A ^ Now add a second drip to the simulation . Observe the interference of the two water waves. Comment on the interference of the two waves: l A reas -{-y\o y sec\ ,\ ( \ ( oiA)\ j Show Screen Add a second light source and view the interfering waves and the pattern they create on the screen , jI - Showing the Intensity Graph quantifies the energy that is incident upon the screen. What effect does amplitude have on the maxima separation in the interference pattern? -Vhf wxk^ rSecrAr &_ pattern Jugf , , ^ What effect does source spacing have on the maxima separation in the interference pattern 7 u . ^ Reset the light waves simulation and show the screen and graph. • • • Add a 2-slit barrier to the simulation and allow the graphs to be formed. ^ P.S jy 1111 m fV v f r ^TTT Observe the interference pattern created when the characteristics of the simulation are adjusted. You may have to adjust amplitude when other elements of the simulation are changed to observe the graph. -Aft ‘ * (e ' m Part III: Light Wave Diffraction • * ( an? r los, v -fogg-H'Xg r Vherf fs LCJS fA-ferfery Ateut \j J , • JtfvpaHv . r l rterf VM YYWc f ere c \ A iVAin the interference pattern? A \ il [kA ' does wavelength have on the maxima separation What effect 'MT Cw\\r . t f j) & ^ more striper , moh? inhpfprtmce , wWh • wvc f Please note the waves take some time to settle out and show good graphs-be patient Part II: Light Wave Interference • t A ^ drop v hC * What effect does a larger amplitude have on the maxima separation in the interference pattern? 'T -- ck 0-c s n ’ r o> e w\ j o & yv\ o What effect does a shorter wavelength have on the maxima separation in the interference pattern? - barn er- Severn Ais-h What effect does a larger barrier to screen distance have on the maxima separation in the interference pattern? — ' CkVC ’VAftre DU What effect does a smaller slit width have on the maxima separation in the interference pattern? S(Y\ , Sh><; , - j -tru? ? % CLnSrr K L 1 What effect does a smaller slit separation have on the maxima separation in the interference pattern? , g ( ih - para hbiA V -iW -f -h& r I tngc , Conclusion Questions and Calculations: You may check your approximate answers in the simulation 1. Why would a helicopter passing over or near a TV antenna cause a garbled or unusable TV signal? W\e hil iropW uphold~ Cul aQ . v% * lufrvys , ( 3. As wavelength of the incident light increases ( blue-> red ) the maxima separatioi er ) <% * ^ H * / mcreSSy decreases. blvve / r /S ter i h i t ur ' 1 U.W 5 U pa r t ( i \ is t f ,