PROBLEMS
- A textured ceiling tile is designed to cancel sound waves of frequency 1000 Hz. What depth must the recesses have? Assume the speed of sound in air is 340m/s.
- What fraction of the intensity of sound of frequency 800 Hz would reflect off the tiles in the previous problem?
- An aluminum bicycle handlebar is anodized so that it appears red at a wavelength of 610 nm. What is the thickness of the anodized layer of refractive index 1.6? The anodizing material has smaller refractive index than the aluminum.
- A camera has a thin film coating applied to the outer face of its lens. What is the purpose of this film?
- If the film in the prior problem has a refractive index of 1.7 while the glass lens has an index of 1.5, what is the thinnest layer that could be applied? Second thinnest?
- Laser light of wavelength 600 nm is incident on a double slit (d=0.10 mm) setup (ideal double slit). A screen is placed 2.0 m away. How far is the first bright fringe from the central maximum? What is the distance to the 3rd minimum from center? What is the width of the central maximum?
- How many little "bumps" fit between the big peaks of the intensity pattern while using a slit with n=5? What is the spacing between the big peaks in phase angle in terms of n?
- In the limit as N becomes large, as in the case of a diffraction grating, what will the pattern look like on a screen? Perhaps use a drawing rather than words.
- 8.6cm
- 9.5%
- 191nm
- To prevent reflection and send more light through the lens.
- 162nm and 324nm
- 1.2cm; 3.0cm; 1.2cm
- 3 little "bumps";
- Narrow peaks with essentially darkness between them. The peaks will darken away from the central peak due to the single slit envelope.