Part A Sound with frequency 1290 Hz leaves a room through a doorway with a width of 1.17 m. At what minimum angle relative to the centerline perpendicular to the doorway will someone outside the room hear no sound? Use 344 m/s for the speed of sound in air and assume that the source and listener are both far enough from the doorway for Fraunhofer diffraction to apply. You can ignore effects of reflections. Express your answer in radians.

Part A One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. Having recently studied optics in your physics class, you're not too surprised to see that the patch of light seems to be a circular diffraction pattern. It appears that the central maximum is about 3 cm across, and you estimate that the distance from the window Estimate the average wavelength of the sunlight (in nm). shade to the wall is about 5 mn O 350 nm 450 nm O 550 nm O 650 nm O 750 nm Submit Previous Answers v Correct Part B Estimate the diameter of the pinhole (in mm). Express your answer using one significant figure. IXI x•10" d = 1.83 • 10¯2 mm Submit Previous Answers Request Answer X Incorrect; Try Again; 5 attempts remaining

A light source is directed through a diffraction grating such that it produces an interference pattern on a screen. If the spectrum on the screen is nearly continuous, with the exception of 3 small dark lines. Which of the following is most likely the light source? O A white light source O A white light source passing through a cool gas O An electrically charged gas O A hot gas

Part A (Figure 1) shows a light wave incident on and passing through a thin soap film. Reflections from the front and back surfaces of the film create smaller waves (not shown in the figure) that travel to the left of the film, where they interfere. What is the thickness of the film in terms of the light wavelength inside it? Express your answer as a multiple of wavelength to two significant figures. Πνα ΑΣφ d = Submit Request Answer Part B Figure 1 of 1 Do the reflections from the film surfaces have a phase shift or not? O Reflections from the both surfaces of the film do not have a phase shift. Soap film Reflection from the right surface of the film has a phase shift while reflection f film does not have a phase shift. Reflection from the left surface of the film has a phase shift while reflection fro film does not have a phase shift. Incident wave Reflections from the both surfaces of the film have a phase shift. Submit Previous Answers

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A 580 lines/mm diffraction grating is in an empty aquarium tank. The index of refraction of the glass walls is nglass = 1.50. A helium-neon laser (λ = 633nm) is outside the aquarium. The laser beam passes through the glass wall and illuminates the diffraction grating. Part A What is the first-order diffraction angle of the laser beam? Express your answer with the appropriate units. ► View Available Hint(s) 0₁ = Submit Part B Value 0₁ = Units 1.33)? What is the first-order diffraction angle of the laser beam after the aquarium is filled with water (nwater = Express your answer with the appropriate units. ► View Available Hint(s) Value ? Units ?

Three polarizing filters are stacked, with the polarizing axis of the second and third filters at angles of 24.0° and 62.0°, respectively, to that of the first. If unpolarized light is incident on the stack, the light has an intensity of 69.5 W/cm² after it passes through the stack. Part A If the incident intensity is kept constant but the second polarizer is removed, what is the intensity of the light after it has passed through the stack? Express your answer with the appropriate units. I = Value W cm² www. Submit Previous Answers Request Answer ?