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AP Physics B - Physical Optics Objectives
- Students should understand the interference and diffraction of waves so they can apply the principles of interference to coherent sources oscillating in phase in order to::
- Describe the conditions under which the waves reaching an observation point from two or more sources will all interfere constructively, or under which the waves from two sources will interfere destructively.
- Determine locations of interference maxima or minima for two sources or determine the frequencies or wavelengths that can lead to constructive or destructive interference at a certain point.
- Relate the amplitude and intensity produced by two or more sources that interfere constructively to the amplitude and intensity produced by a single source.
- Students should understand the interference and diffraction of waves so they can apply the principles of interference and diffraction to waves that pass through a single or double slit or through a diffraction grating so they can:
- Sketch or identify the intensity pattern that results when monochromatic waves pass through a single slit and fall on a distant screen, and describe how this patter will change if the slit width or the wavelength of the waves is change.
- Calculate, for a single slit pattern, the angles or the positions on a distant screen where the intensity is zero.
- Sketch or identify the intensity pattern that results when monochromatic waves pass through a double slit, and identify which features of the pattern result from single-slit diffraction and which from two-slit interference.
- Calculate, for a two-slit interference pattern, the angles or the positions on a distant screen at which intensity maxima or minima occur.
- Describe or identify the interference pattern formed by a grating of many equally spaced narrow slits, calculate the location of intensity maxima, and explain qualitatively why a multiple-slit grating is better than a two-slit grating for making accurate determination of wavelength.
- Apply the principles of interference to light reflected by thin films so they can:
- State under what conditions a phase reversal occurs when light is reflected from the interface between two media of different indices of refraction.
- Determine whether rays of monochromatic light reflected from two such interfaces will interfere constructively or destructively, and thereby account for Newton's rings adn similar phenomena, and explain how glass may be coated to minimize reflection of visible light.
- Students should understand dispersion and the elctromagnetic spectrum so they can:
- Rleate a variation of index of refraction with frequency to a variation in refraction.
- Know the names associated with the electromagnetic radiation and be able to arrange in order of increasing wavelength the following: visible light of various colors, ultraviolet light, infrared light, radio waves, x-rays, and gamma rays.
- Students should understand the transverse nature of light waves so they can explain qualitatively why light can exhibit polarization.
- Students should understand the inverse-square law so they can calculate the intensity of light at a given distance from a source of specified power and compare the intensity of light at different distances from the source.