At night many people see rings (called entoptic halos) surrounding bright outdoor lamps in otherwise dark surroundings. The rings are the first of the side maxima in diffraction patterns produced by structures that are thought to be within the cornea (or possibly the lens) of the observer’s eye. (The central maxima of such patterns overlap the lamp.) (a) Would a particular ring become smaller or larger if the lamp were switched from blue to red light? (b) If a lamp emits white light, is blue or red on the outside edge of the ring?

Two light beams are incident normal to one surface of a triangular prism with refractive index n = 1.4 surrounded by air. What is the value of the angle between the two emerging beams, shown as a in the figure? d a 90° d 45° O 70.4° 73.7° O 61.8° 60.0° O 65.8° ..... ......

Information is stored on an audio compact disc, CD-ROM, or DVD disc in a series of pits on the disc. These pits are scanned by a laser beam. An important limitation on the amount of information that can be stored on such a disc is the width of the laser beam. Explain why this should be, and explain how using a shorter-wavelength laser allows more information to be stored on a disc of the same size. With which color of light can the Hubble Space Telescope see finer detail in a distant astronomical object: red, blue, or ultraviolet? Explain your answer.

You stand on a straight desert road at night and observe a vehicle approaching. This vehicle is equipped with two small headlights that are 0.635 m apart. At what distance, in kilometers, are you marginally able to discern that there are two headlights rather than a single light source? Take the wavelength of the light to be 537 nm and your pupil diameter to be 5.17 mm.

Fiber optic cables, such as those used for high speed communication (Internet & phone services), transmit signals as light pulses through transparent cables. When viewed from one of the ends, you can see these light pulses, but when viewed from the side you can't. Why does this happen?

The Rayleigh criterion provides a convenient way to describe the theoretical resolution (e.g. an ability to distinguish two bright objects ) of an optical system. The criterion states that two small bright sources of light can be resolved if the first diffraction minimum of the image of one source point just coincides with of further apart then the first maximum of another (see figure below). A converging lens, 34.2 mm in diameter, is used to form images of distant objects. Considering the diffraction by the lens, what angular separation must two distant point objects have in order to satisfy Rayleigh's criterion? Assume that the wavelength of the light from the distant objects is 431 nm. Provide your answer in millidegrees (mdeg). Answer: Choose... +

The limit to the eye's acuity is actually related to diffraction by the pupil. What is the angle between two just-resolvable points of light for a 2.75 mm diameter pupil, assuming the average wavelength of 539 nm? angle between two points of light: Take the result to be the practical limit for the eye. What is the greatest possible distance a car can be from a person if he or she can resolve its two headlights, given they are 1.40 m apart? greatest distance at which headlights can be distinguished: m What is the distance between two just-resolvable points held at an arm's length (0.900 m) from a person's eye? distance between two points 0.900 m from a person's eye: m

A lens with an index of refraction of 1.60 is to be coated with a material (n = 1.40) that will make the lens nonreflecting for yellow-orange light (λλ = 515 nm) normally incident on the lens. What is the minimum required thickness of the coating?