Physics (5th Edition)
5th Edition
ISBN: 9780321976444
Author: James S. Walker
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 25, Problem 61PCE
(a)
To determine
The amount of energy absorbed by eyes in
0.2 s
(b)
To determine
The average intensity of light on the spot of the retina.
(c)
To determine
The factor by which average intensity of laser beam has been exceeded from the safe value to damage the retina.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
Laser Safety A 0.95 mW laser emits a narrow beam of light that enters the eye. d=5.0 um
a. How much energy is absorbed by the eye in 0.20 s?
b. The eye focuses this beam to a tiny spot on the retina, perhaps 5.0 μm in diameter. What is the average intensity of light at this spot?
2
A LASIK vision correction system uses a laser that emits 10-ns-long pulses of light,
each with 2.5 mJ of energy. The laser is focused to a 0.85-mm-diameter circle.
a. What is the average power of each laser pulse in units of watts?
b. Determine the intensity of the laser light at the focus point.
c. What is the electric field amplitude of the laser light at the focus point?
Chapter 25 Solutions
Physics (5th Edition)
Ch. 25.1 - Enhance Your Understanding (Answers given at the...Ch. 25.2 - A distant galaxy is moving away from the Earth....Ch. 25.3 - If the frequency of an electromagnetic wave is...Ch. 25.4 - Prob. 4EYUCh. 25.5 - In the system shown in Figure 25-36, a vertically...Ch. 25 - Explain why the invisible man would be unable to...Ch. 25 - While wearing your Polaroid sunglasses at the...Ch. 25 - You want to check the tine while wearing your...Ch. 25 - BIO Polarization and the Ground Spider The ground...Ch. 25 - You are given a sheet of Polaroid material....
Ch. 25 - Can sound waves be polarized? Explain.Ch. 25 - At a garage sale you find a pair of Polaroid...Ch. 25 - If the electric field in an electromagnetic wave...Ch. 25 - Prob. 2PCECh. 25 - Prob. 3PCECh. 25 - Prob. 4PCECh. 25 - Give the direction (N, S, E, W, up, or down) of...Ch. 25 - Prob. 6PCECh. 25 - Prob. 7PCECh. 25 - The light year (ly) is a unit of distance commonly...Ch. 25 - Alpha Centauri, the closest star to the Sun, is...Ch. 25 - Prob. 10PCECh. 25 - A fighter jet is traveling at 515 m/s directly...Ch. 25 - A distant star is traveling directly away from...Ch. 25 - Prob. 13PCECh. 25 - Prob. 14PCECh. 25 - Prob. 15PCECh. 25 - Prob. 16PCECh. 25 - Communicating with the Voyager Spacecraft The...Ch. 25 - A father and his daughter are interested in the...Ch. 25 - Prob. 19PCECh. 25 - Prob. 20PCECh. 25 - Prob. 21PCECh. 25 - Baseball scouts often use a radar gun to measure...Ch. 25 - A state highway patrol car radar unit uses a...Ch. 25 - Prob. 24PCECh. 25 - Prob. 25PCECh. 25 - BIO Dental X-rays The X-rays produced in the...Ch. 25 - Find the frequency of green light with a...Ch. 25 - Prob. 28PCECh. 25 - How many led wavelengths ( = 705 nm) tall are you?Ch. 25 - A cell phone transmits at a frequency of 1.94 ...Ch. 25 - Microwave Oven If a microwave oven produces...Ch. 25 - BIO Human Radiation Under normal conditions,...Ch. 25 - BIO UV Radiation Ultraviolet light is typically...Ch. 25 - Prob. 34PCECh. 25 - Predict/Calculate When an electromagnetic wave...Ch. 25 - Predict/ Calculate (a) Which color of light has...Ch. 25 - Prob. 37PCECh. 25 - A television is tuned to a station broadcasting at...Ch. 25 - An AM radio stations antenna is constructed to be...Ch. 25 - Prob. 40PCECh. 25 - Find the difference in wavelength (1 2) for each...Ch. 25 - Synchrotron Frequency In one portion of a...Ch. 25 - Prob. 43PCECh. 25 - Prob. 44PCECh. 25 - Prob. 45PCECh. 25 - What is the rms value of the electric field in a...Ch. 25 - The magnetic field in an electromagnetic wave has...Ch. 25 - What is the maximum value of the electric field in...Ch. 25 - What is the maximum value of the electric field in...Ch. 25 - Predict/Calculate Electromagnetic wave 1 has a...Ch. 25 - A 75-kW radio station broadcasts its signal...Ch. 25 - At what distance will a 45-W lightbulb have the...Ch. 25 - What is the ratio of the sunlight intensity...Ch. 25 - Predict/Calculate In the following, assume that...Ch. 25 - Prob. 55PCECh. 25 - Prob. 56PCECh. 25 - Sunlight Intensity After filtering through the...Ch. 25 - Predict/Calculate (a) Find the electric and...Ch. 25 - Prob. 59PCECh. 25 - BIO You are standing 2.5 m from a 150-W lightbulb....Ch. 25 - Prob. 61PCECh. 25 - Find the rms electric and magnetic fields al a...Ch. 25 - Prob. 63PCECh. 25 - Prob. 64PCECh. 25 - Prob. 65PCECh. 25 - BIO Laser Surgery Each pulse produced by an...Ch. 25 - Prob. 67PCECh. 25 - Predict Explain Consider the two polarization...Ch. 25 - Predict/Explain Consider the two polarization...Ch. 25 - An incident beam of light with an intensityl0....Ch. 25 - Vertically polarized light with an intensity of...Ch. 25 - A person riding in a boat observes that the...Ch. 25 - Unpolarized light passes through two polarizers...Ch. 25 - In Problem 73, what should be the angle between...Ch. 25 - Unpolarized light is incident with intensity /0 on...Ch. 25 - Predict/Calculate A beam of vertically polarized...Ch. 25 - Predict/Calculate Repeat Problem 76, this time...Ch. 25 - BIO Predict/Calculate Optical Activity Optically...Ch. 25 - A helium-noon laser omits a beam of unpolarizod...Ch. 25 - Referring to Figure 25-46, suppose that filter 3...Ch. 25 - Prob. 81GPCh. 25 - CE If sailors of the future use radiation pressure...Ch. 25 - Prob. 83GPCh. 25 - BIO Radiofrequency Ablation In radiofrequency (RF)...Ch. 25 - Predict/Calculate At a particular instant of time,...Ch. 25 - Predict/Calculate A light beam traveling in the...Ch. 25 - Figure 25-47 shows four polarization experiments...Ch. 25 - Lightning and Thunder During a thunderstorm a bolt...Ch. 25 - Prob. 89GPCh. 25 - Prob. 90GPCh. 25 - Predict/Calculate Suppose the distance to the...Ch. 25 - BIO Predict/Calculate Consider the physical...Ch. 25 - BIO Polaroid Vision in a Spider Experiments show...Ch. 25 - A state highway patrol car radar unit uses a...Ch. 25 - What is the ratio of the sunlight intensity...Ch. 25 - What area is needed for a solar collector to...Ch. 25 - Prob. 97GPCh. 25 - Three polarizers are arranged as shown in Figure...Ch. 25 - Prob. 99GPCh. 25 - Orbital Drift The radiation pressure exerted by...Ch. 25 - A lightbulb emits light uniformly in all...Ch. 25 - Radio Reception A 125-kW radio station broadcasts...Ch. 25 - Light Rocket Stranded 12 m from your spacecraft,...Ch. 25 - A typical home may require a total of 2.00 103...Ch. 25 - Prob. 105GPCh. 25 - Predict/Calculate A typical laser used in...Ch. 25 - Four polarizers are set up so that the...Ch. 25 - BIO Optical Activity of Sugar The sugar...Ch. 25 - Visible-Light Curing in Dentistry An essential...Ch. 25 - Visible-Light Curing in Dentistry An essential...Ch. 25 - Visible-Light Curing in Dentistry An essential...Ch. 25 - Visible-Light Curing in Dentistry An essential...Ch. 25 - Predict/Calculate Referring to Example 25-12...Ch. 25 - Referring to Example 25-12 Suppose the incident...
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
- A community plans to build a facility to convert solar radiation to electrical power. The community requires 1.00 MW of power, and the system to be installed has an efficiency of 30.0% (that is, 30.0% of the solar energy incident on the surface is converted to useful energy that can power the community). Assuming sunlight has a constant intensity of 1 000 W/m2, what must be the effective area of a perfectly absorbing surface used in such an installation?arrow_forwardLunar astronauts placed a reflector on the Moon's Surface, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. (a) To what accuracy in meters can the distance to the Moon be determined, if this time can be measured to 0.100 ns? (b) What percent accuracy is this, given the average distance to the Moon is 3.84108m ?arrow_forwardCASE STUDY In Example 34.6 (page 1111), we imagined equipping 1950DA, an asteroid on a collision course with the Earth, with a solar sail in hopes of ejecting it from the solar system. We found that the enormous size required for the solar sail makes the plan impossible at this time. Of course, there is no need to eject such an object from the solar system: we only need to change the orbit. A much more pressing problem is Apophis, a 300-m asteroid that may be on a collision course with the Earth and is due to come by on April 13, 2029. It is unlikely to hit the Earth on that pass, but it will return again in 2036. If Apophis passes through a 600-m keyhole on its 2029 pass, it is expected to hit the Earth in 2036. causing great damage. There are plans to deflect Apophis when it comes by in 2029. For example, we could hit it with a 10- to 150-kg impactor accelerated by a solar sail. The impactor is launched from the Earth to start orbiting the Sun in the same direction as the Earth and Apophis. The idea is to use a solar sail to accelerate the impactor so that it reverses direction and collides head-on with Apophis at 8090 km/s and thereby keeps Apophis out of the keyhole. Consider the momentum in the impactors orbit (Fig. P34.75) when the solar sail makes an angle of = 60 with the tangent to its orbit. Current solar sails may be about 40 m on a side, but the hope is to construct some that are about 160 m on a side. Estimate the impactors tangential acceleration when it is about 1 AU from the Sun. Keep in mind that the sail is neither a perfect absorber nor a perfect reflector, and a heavier impactor would presumably be equipped with a larger sail. Dont be surprised by what may seem like a very small acceleration. FIGURE P34.75arrow_forward
- Professor Edward Ney was the founder of infrared astronomy at the University of Minnesota. In his later years, he wore an artificial pacemaker. Always an experimentalist, Ney often held a strong laboratory magnet near his chest to see what effect it had on his pacemaker. Perhaps he was using the magnet to throw switches that control different modes of operation. An admiring student (without an artificial pacemaker) thought it would be fun to imitate this great man by holding a strong magnet to his own chest. The natural pacemaker of the heart (known as the sinoatrial node) carries a current of about 0.5 mA. Estimate the magnetic force exerted on a natural pacemaker by a strong magnet held to the chest. How do you think the student might have felt during the experiment? Explain your geometric assumptions. Hints: See Table 30.1 (page 941) to estimate the magnetic field, and assume the field is roughly uniform. Use Figure P30.58 to estimate the size of the sinoatrial node; your heart is about the size of your fist. FIGURE P30.58arrow_forward(a) What is the wavelength of a 1.00-eV photon? (b) Find its frequency in hertz. (c) Identify the type of EM radiation.arrow_forwardA plane electromagnetic wave of frequency 20 GHz moves in the positive y-axis direction such that its electric field is pointed along the z-axis. The amplitude of the electric field is 10 V/m. The start of time is chosen so that at t = 0, the electric field has a value 10 V/m at the origin. (a) Write the wave function that will describe the electric field wave, (b) Find the wave function that will describe the associated magnetic field wave.arrow_forward
- A spherical interplanetary grain of dust of radius 0.2 m is at a distance r1 from the Sun. The gravitational force exerted by the Sun on the grain just balances the force due to radiation pressure from the Sun's light. (i) Assume the grain is moved to a distance 2r1 from the Sun and released. At this location, what is the net force exerted on the grain? (a) toward the Sun (b) away from the Sun (c) zero (d) impossible to determine without knowing the mass of the grain (ii) Now assume the grain is moved back to its original location at r1, compressed so that it crystallizes into a sphere with significantly higher density, and then released. In this situation, what is the net force exerted on the grain? Choose from the same possibilities as in part (i).arrow_forwardRadio station WWVB, operated by the National Institute of Standards and Technology (NIST) from Fort Collins, Colorado, at a low frequency of 60 kHz, broadcasts a time synchronization signal whose range covers the entire continental US. The timing of the synchronization signal is controlled by a set of atomic clocks to an accuracy of 101012 s, and repeats every 1 minute. The signal is used for devices, such as radio-controlled watches, that automatically synchronize with it at preset local times. WWVB's long wavelength signal tends to propagate close to the ground. (a) Calculate the wavelength of the radio waves from WWVB. (b) Estimate the error that the travel time of the signal causes in synchronizing a radio controlled watch in Norfolk, Virginia, which is 1570 mi (2527 km) from Fort Collins, Colorado.arrow_forwardSuppose you are located 180 in from a radio transmitter. (a) How many wavelengths are you from the transmitter if the station calls itself 1150 AM? (The AM band frequencies are in kilohertz.) (b) What if this station is 98.1 FM? (The FM band frequencies are in megahertz.)arrow_forward
- If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m calculate the peak values of E and B. O 1000 V/m, 3.35x10-6 T O 111 V/m, 3. 00×10 5 T O 711 V/m, 2 37×10-6 T O 300 V/m. 10 T O 225 V/m, 1. 60' 10-3 T Next pagearrow_forwardA 3[A] current is passed through a parallel-plate capacitor sandwiching a dielectric with constant K=2. Which of the following is true about the displacement current iD between the capacitor plates? A. ;D = 0 since no current passes through a dielectric unless there is a dielectric breakdown B. D 3 [A] since a dielectric increases voltage capacity and hence the displacement current via Ohm's lawarrow_forwardRight naaoarrow_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
Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers with Modern ...
Physics
ISBN:9781337553292
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College