When the eye sees a star (a point of light), the pupil spreads by diffraction the image of the star to a small round spot on the retina. Suppose the light from the star has a wavelength of m. When the pupil is at its largest, it may have a diameter of 7.0 mm. a) If the distance from the pupil to the retina is 23 mm, what then is the diameter of the image of the star on the retina? In the middle of retina, there are approx. 150,000 light-sensitive cells per . b) How many of these cells are illuminated when the eye looks at the star?

When the eye sees a star (a point of light), the pupil spreads by diffraction the image of the star to a small round spot on the retina. Suppose the light from the star has a wavelength of m. When the pupil is at its largest, it may have a diameter of 7.0 mm. a) If the distance from the pupil to the retina is 23 mm, what then is the diameter of the image of the star on the retina? In the middle of retina, there are approx. 150,000 light-sensitive cells per . b) How many of these cells are illuminated when the eye looks at the star?

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter30: Sensory Perception

Section: Chapter Questions

Problem 2CT

See similar textbooks

Similar questions

The human retina has three types of receptor cones, eachsensitive to a different range of wavelengths of visible light,as shown in this figure (the colors are merely to differentiatethe three curves from one another; they do not indicate theactual colors represented by each curve):(a) Estimate the energies of photons with wavelengths at themaximum for each type of cone. (b) The color of the sky is dueto scattering of solar light by the molecules of the atmosphere.Lord Rayleigh was one of the first to study scattering of thiskind. He showed that the amount of scattering for very smallparticles such as molecules is inversely proportional to thefourth power of the wavelength. Estimate the ratio of the scatteringefficiency of light at the wavelength of the maximumfor the “blue” cones, as compared with that for the “green”cones. (c) Explain why the sky appears blue even though allwavelengths of solar light are scattered by the atmosphere
Since the visual images areprojected in an invertedmanner on the retina whydon't we see things upsidedown?
Very short pulses of high-intensity laserbeams are used to repair detached portions of the retina of the eye. Thebrief pulses of energy absorbed by the retina weld the detached portionsback into place. In one such procedure, a laser beam has a wavelengthof 810 nm and delivers 250 mW of power spread over a circularspot 510 mm in diameter. The vitreous humor (the transparent fluid thatfills most of the eye) has an index of refraction of 1.34. If the laser pulses are each 1.50 ms long, how much energy is delivered to the retina with each pulse?
Suppose you measure the scanning (4x) field of vision diameter with a stage micrometer and it is 2 mm. If high power is 40X, and gives 10X more magnification than scanning power, how big will the diameter of the field of vision be using high power?
During a recent Alaskan cruise, Max and his grandfather were staringat a glacier some distance from their tour boat. Suddenly, Max’s motherinterrupted them to show them a piece of ice one of the deck handshad scooped from the water in the bay. Max was able to focus on thepiece of ice and see its clear blue features, but his grandfather had toreach for his glasses. What changes occurred in their eyes between thetime they were staring at the glacier and the time they were looking atthe piece of ice? Explain why Max’s grandfather reached for his glasses
What color does an object appear if it absorbs light at both 420-500 nm and at 620-700 nm? a. Red b. Black c. Purple d. Green e. Deep blue
In a converging lens, if an incident ray is parallel to the principle axis, the reflected ray ____________. 2. In a diverging lens, if an incident ray is parallel to the principle axis, the reflected ray ____________. 3. Can a real image be obtained by means of a diverging lens? If yes, how?
Suppose you conduct direct visible spectrophotometry with red fruit punch as your solution. Which wavelengths of light would you expect to be strongly absorbed? Which wavelengths are not strongly absorbed? Explain.
Figure Q9–2 shows a diagram of the human eye. Therefractive indices of the components in the light path are:cornea 1.38, aqueous humor 1.33, crystalline lens 1.41, andvitreous humor 1.38. Where does the main refraction—themain focusing—occur? What role do you suppose the lensplays?
The human eye is much like a camera—yet, when a camerashutter is left open and the camera is moved, the image willbe blurred. But when you move your head with your eyesopen, you still see clearly. Explain
For dispersion of light through a prism which colour has maximum deviation?
In a condition called presbyopia, the eyes’ lenses lose muchof their elasticity and maintain a flat shape. How wouldyou expect this condition to affect a person’s vision?