University:
College
Course:
College Physics
Academic year:

2023
Views:

466

Pages:

4
Author:

anon

Wave Properties 1.Describe the reflection and transmission of waves at a boundary between two media Usually, when a wave meets the boundary between two different media it is partially reflected and partially trasmitted. As you can see from the diagram, there is a red line dividing the two ‘mediums”. You should know that the Medium below is denser than the medium above. 2. State and apply Snell’s law Snell’s Law states that the ratio : V= Velocity The two sines divided by each other is also equal to “k”, which is a constant for a given frequency. 3. Explain and discuss qualitatively the diffraction of waves at apertures and obstacles When waves pass through apertures they tend to spread out. Waves also spread around obstacles. This is called diffraction. -The wavelength needs to of the same order of magnitude as the aperture for diffraction to be noticeable. -Diffraction becomes important when the wavelength is large in comparison to size of aperture. 4. Describe examples of diffraction -Provides explanation of why we can hear something but cannot see it. If the Wavelength= Aperture Length, a perfect diffraction occurs, therefore the sound wave spreads perfectly, allowing people close by to hear the sound, but not necessarily see the able. -If you look at a distant street light at night and then squint your eyes the light spreads sideways—This is because of the diffraction taking place around your eyelashes. 5. State the principle of superposition and explain what is meant by constructive interference and by destructive interference When two waves of the same type meet, they interfere with each other, and we can work out the resulting wave using the “Principle of Superposition”. The overall disturbance at any point and at any time where waves meet is the vector sum of the disturbances that would have been produced by each of the individual wave. As you can see, the two waves below are added together like a vector to produce the final result at the top. When waves that have the same amplitude and frequency interfere with each other, then the interference at a particular point can be either constructive or destructive. Constructive Destructive Interference 6. State and apply the conditions for constructive and for destructive interference in terms of path difference and phase difference. Constructive Interference takes place when the two waves are “in step” with one another—aka. In phase. Destructive Interference takes place when the waves are exactly “out of step”–they are said to be “out of phase” Interference can take place if there are two possible routes for a ray to travel from source to observer. If the path difference between the two rays is a whole number of wavelengths, Constructive Interference will take place. Path Difference: n x wavelength= constructive Path Difference: (n+1/2) x wavelength= destructive n=0,1,2,3 7. Apply the principle of superposition to determine the resultant of two waves This is simply the vector sum of the waves that are in phase with each other.