Essential University Physics
4th Edition
ISBN: 9780134988566
Author: Wolfson, Richard
Publisher: Pearson Education,
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 30, Problem 63P
Fermat's principle states that a light ray's path is such that the time to traverse that path is an extremum (a minimum or a maximum) when compared with times for nearby paths. Show that Fermat's principle implies Snell's law by proving that a light ray going from point A in one medium to point B in a second medium will take the least time if it obeys Snell's law.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Let v, be the velocity of light in air and vz the velocity of
light in water. According to Fermat's Principle, a ray of
light will travel from a point A in the air to a point B in the
water by a path ACB that minimizes the time taken. Show
that
sin 0
sin 02
where 01 (the angle of incidence) and 02 (the angle of
refraction) are as shown. This equation is known as Snell's
Law.
B
Edward and Calil do some experiments to determine the speed of light in a special
transparent material. They determine the speed of light to be 0.63c. Edward
shines a light thru the material. Determine the critical angle in degrees for the
light ray if there is a chamber of air above the material. Please give your answer as
a whole number. (c is the speed of light in vacuum)
When the sun is either rising or setting and appears to be just on the horizon, it is in fact below the horizon. The explanation for this seeming paradox is that light from the sun bends slightly when entering the earth’s atmosphere, as shown in Fig. Since our perception is based on the idea that light travels in straight lines, we perceive the light to be coming from an apparent position that is an angle d above the sun’s true position. (a) Make the simplifying assumptions that the atmosphere has uniform density, and hence uniform index of refraction n, and extends to a height h above the earth’s surface, at which point it abruptly stops. Show that the angle d is given by as attached. where R = 6378 km is the radius of the earth. (b) Calculate d using n = 1.0003 and h = 20 km. How does this compare to the angular radius of the sun, which is about one quarter of a degree? (In actuality a light ray from the sun bends gradually, not abruptly, since the density and refractive index of the…
Chapter 30 Solutions
Essential University Physics
Ch. 30.1 - Prob. 30.1GICh. 30.2 - The figure shows the path of a light ray through...Ch. 30.3 - The glass prism in Fig. 30.11 has n = 1.5 and is...Ch. 30.4 - Prob. 30.4GICh. 30 - Prob. 1FTDCh. 30 - Why does a spoon appear bent when its in a glass...Ch. 30 - Prob. 3FTDCh. 30 - Prob. 4FTDCh. 30 - You send white light through two identical glass...Ch. 30 - In glass, which end of the visible spectrum has...
Ch. 30 - Prob. 7FTDCh. 30 - Why are polarizing sunglasses better than glasses...Ch. 30 - Under what conditions will the polarizing angle be...Ch. 30 - Through what angle should you rotate a mirror so...Ch. 30 - Prob. 12ECh. 30 - To what angular accuracy must two ostensibly...Ch. 30 - Prob. 14ECh. 30 - In which substance in Table 30.1 does the speed of...Ch. 30 - Information in a compact disc is stored in pits"...Ch. 30 - Light is incident on an air-glass interface, and...Ch. 30 - A light ray propagates in a transparent material...Ch. 30 - Light propagating in the glass (n = 1.52) wall of...Ch. 30 - Prob. 20ECh. 30 - Find the refractive index of a material for which...Ch. 30 - Find the critical angle for total internal...Ch. 30 - A drop of water is trapped in a block of ice....Ch. 30 - What is the critical angle for light propagating...Ch. 30 - Total internal reflection occurs at an interface...Ch. 30 - Blue and red laser beams strike an air-glass...Ch. 30 - White light propagating in air is incident at 45...Ch. 30 - Example 30.2: Take the slab in Fig 30.6 to be...Ch. 30 - Example 30.2: Take θ1 = 32.5° in Fig 30.6. (a) If...Ch. 30 - Prob. 30ECh. 30 - Prob. 31ECh. 30 - Prob. 32ECh. 30 - Prob. 33ECh. 30 - Prob. 34ECh. 30 - Prob. 35ECh. 30 - Suppose the 60 angle in Fig. 30.18 is changed to...Ch. 30 - The refractive index of a human cornea is 1.40. If...Ch. 30 - Two plane mirrors make an angle . A light ray...Ch. 30 - An unlabeled bottle of liquid has spilled, and...Ch. 30 - A meter stick lies on the bottom of the...Ch. 30 - Prob. 41PCh. 30 - At the aquarium where you work, a fish has gone...Ch. 30 - Prob. 43PCh. 30 - You've dropped your car keys at night off the end...Ch. 30 - Laser eye surgery uses ultraviolet light with...Ch. 30 - Prob. 46PCh. 30 - Where and in what direction would the main beam...Ch. 30 - Find the speed of light in a material for which...Ch. 30 - Prob. 49PCh. 30 - For the interface between air (refractive index 1)...Ch. 30 - A scuba diver sets off a camera flash at depth h...Ch. 30 - Suppose the red and blue beams of Exercise 26 are...Ch. 30 - In cataract surgery, ophthalmologists replace the...Ch. 30 - In a ruby laser, light is produced in a solid rod...Ch. 30 - An optical fiber with circular cross section has...Ch. 30 - A cylindrical tank 2.4 m deep is full to the brim...Ch. 30 - For what diameter tank in Problem 50 will sunlight...Ch. 30 - Prob. 58PCh. 30 - Prob. 59PCh. 30 - (a) Differentiate the result of Problem 55 to show...Ch. 30 - Prob. 61PCh. 30 - Show that a three-dimensional corner reflector...Ch. 30 - Fermat's principle states that a light ray's path...Ch. 30 - Prob. 64PCh. 30 - A slab of transparent material has thickness d and...Ch. 30 - For common materials like glass, the wavelength...Ch. 30 - Figure 30.25a depicts lights path over a hot road,...Ch. 30 - Prob. 68PPCh. 30 - Figure 30.25b shows how continuous refraction in...Ch. 30 - The refractive index in the ionosphere is strongly...
Additional Science Textbook Solutions
Find more solutions based on key concepts
What is the role of “loose” electrons in heat conductors?
Conceptual Physics (12th Edition)
Find the speed of a satellite in geostationary orbit.
Essential University Physics: Volume 1 (3rd Edition)
18. (I) How much work must be done to stop a 925-kg car travelling at 95 km/h?
Physics: Principles with Applications
12. A simple magnifying glass produces a
real inverted image.
real upright image.
virtual inverted image.
virtu...
College Physics (10th Edition)
Q2.1 Does the speedometer of a car measure speed or velocity? Explain.
University Physics with Modern Physics (14th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- What happens to a light wave when it travels from air into glass? (a) Its speed remains the same. (b) Its speed increases. (c) Its wavelength increases. (d) Its wavelength remains the same. (e) Its frequency remains the same.arrow_forwardUnpolarized light in vacuum is incident onto a sheet of glass with index of refraction n. The reflected and refracted rays are perpendicular to each other. Find the angle of incidence. This angle is called Brewsters angle or the polarizing angle. In this situation, the reflected light is linearly polarized, with its electric field restricted to be perpendicular to the plane containing the rays and the normal.arrow_forwardLight passes from a material with index of refraction 1.3 into one with index of refraction 1.2. Compared with the incident ray, what happens to the refracted ray? (a) It bends toward the normal. (b) It is undeflected. (c) It bends away from the normal.arrow_forward
- The index of refraction for water is about 43. What happens as a beam of light travels from air into water? (a) Its speed increases to 43c, and its frequency decreases. (b) Its speed decreases to 34c, and its wavelength decreases by a factor of 34. (c) Its speed decreases to 34c, and its wavelength increases by a factor of 43. (d) Its speed and frequency remain the same. (e) Its speed decreases to 34c, and its frequency increases.arrow_forwardOften in optics scientists take advantage of effects that require very high intensity light. To get the desired effect a scientist uses a laser with power P = 0.0065 W to reach an intensity of I = 170 W/cm2 by focusing it through a lens of focal length f = 0.11 m. The beam has a radius of r = 0.0011m when it enters the lens. Randomized VariablesP = 0.0065 WI = 170 W/cm2f = 0.11 mr = 0.0011 Part (a) Express the radius of the beam, rp, at the point where it reaches the desired intensity in terms of the given quantities. (In other words, what radius does the beam have to have after passing through the lens in order to have the desired intensity?) Part (b) Give an expression for the tangent of the angle that the edge of the beam exits the lens with with respect to the normal to the lens surface, in terms of r and f? Part (c) Express the distance, D, between the lens's focal point and the illuminated object using tan(α) and rp. Part (d) Find the distance, D, in centimeters.…arrow_forwardAn experimenter at an optical research company finds it difficult to experiment, as the measuring device that determines the angle φ inside the mirror always interferes with light progression. In this case, it would be good to measure the angle δ outside the mirror. So how does β, the relative angle of reflection with respect to the angle of incidence, relate to the angle δ?arrow_forward
- In Figure (a), a beam of light in material 1 is incident on a boundary at an angle of 28° The extent to which the light is bent due to refraction depends, in part, on the index of refraction n2 of material 2. Figure (b) gives the angle of refraction 02 versus n2 for a range of possible n2 values, from n, = 1.36 to n, = 1.94. What is the speed of light in material 1? 38° 28 28 18 na (a) (b) Number i ! Units m/sarrow_forward(Snell's Law) Let v be the velocity of light in air and w be the velocity of light in water. According to Fermat's principle, a ray of light will travel from a point A in the air to a point B in the water by a path ACB that minimizes the time taken, Find the ratio sin(01) sin(02) in terms of v and w. A C 02 Barrow_forwardIn the figure, light from ray A refracts from material 1 (n₁ = 1.73) into a thin layer of material 2 (n2 = 1.80), crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3 (n3 = 1.40). (a) What is the value of incident angle BA? (b) If 8A is decreased, does part of the light refract into material 3? Light from ray B refracts from material 1 into the thin layer, crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3. (c) What is the value of incident angle Og? (d) If Og is decreased, does part of the light refract into material 3? OB I ng no 121arrow_forward
- As sunlight enters the Earth’s atmosphere, it changes direction due to the small difference between the speeds of light in vacuum and in air. The duration of an optical day is defined as the time interval between the instant when the top of the rising Sun is just visible above the horizon andthe instant when the top of the Sun just disappears below the horizontal plane. The duration of the geometric day is defined as the time interval between the instant a mathematically straight line between an observer and the top of the Sun just clears the horizon and the instant this linejust dips below the horizon. (a) Explain which is longer, an optical day or a geometric day. (b) Find the difference between these two time intervals. Model the Earth’s atmosphere as uniform, with index of refraction 1.000 293, a sharply defined upper surface, and depth 8 614 m. Assume the observer is at the Earth’s equator so that the apparent path of the rising and setting Sun is perpendicular to the horizon.arrow_forwardIn the figure, light from ray A refracts from material 1 (n1 = 1.60) into a thin layer of material 2 (n2 = 1.80), crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3 (n3 = 1.3). (a) What is the value of incident angle θA? (b) If θA is decreased, does part of the light refract into material 3? Light from ray B refracts from material 1 into the thin layer, crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3. (c) What is the value of incident angle θB? (d) If θB is decreased, does part of the light refract into material 3?arrow_forwardWhen light strikes the surface of a medium such as water or glass, its intensity decreases with depth. The Beer-Lambert-Bouguer law states that the percentage of decrease is the same for each additional unit of depth. In a certain lake, intensity decreases about 85% for each additional meter of depth Use a formula to express intensity I as an exponential function of d. (Use I0 to denote the initial intensity.) At what depth will the intensity of light be one-tenth of the intensity of light striking the surface? (Round your answer to two decimal placesarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Convex and Concave Lenses; Author: Manocha Academy;https://www.youtube.com/watch?v=CJ6aB5ULqa0;License: Standard YouTube License, CC-BY