Concept explainers
LASIK eye surgery uses pulses of laser light to shave off tissue from the cornea, reshaping it. A typical LASIK laser emits a 1.0-mm-diameter laser beam with a wavelength of 193 nm. Each laser pulse lasts 15 ns and contains 1.0 mJ of light energy.
a. What is the power of one laser pulse?
b. During the very brief time of the pulse, what is the intensity of the light wave?
Want to see the full answer?
Check out a sample textbook solutionChapter 15 Solutions
College Physics: A Strategic Approach (3rd Edition)
Additional Science Textbook Solutions
Campbell Essential Biology (7th Edition)
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Microbiology with Diseases by Body System (5th Edition)
Campbell Biology: Concepts & Connections (9th Edition)
Human Biology: Concepts and Current Issues (8th Edition)
Campbell Essential Biology with Physiology (5th Edition)
- A possible means of space flight is to place a perfectly reflecting aluminized sheet into orbit around the Earth and then use the light from the Sun to push this solar sail. Suppose a sail of area A = 6.00 105 m2 and mass m =6.00 103 kg is placed in orbit facing the Sun. Ignore all gravitational effects and assume a solar intensity of 1 370 W/m2. (a) What force is exerted on the sail? (b) What is the sails acceleration? (c) Assuming the acceleration calculated in part (b) remains constant, find the time interval required for the sail to reach the moon, 3.84 108 m away, starting from rest at the Earth.arrow_forward(a) What is the frequency of the 193-nm ultraviolet radiation used in laser eye surgery? (b) Assuming the accuracy with which this electromagnetic radiation can ablate (reshape) the cornea is directly proportional to wavelength, how much more accurate can this UV radiation be than the shortest visible wavelength of light?arrow_forwardA certain 60.0-Hz ac power line radiates an electromagnetic wave having a maximum electric field strength of 13.0 kV/m. (a) What is the wavelength of this very-low-frequency electromagnetic wave? (b) What type of electromagnetic radiation is this wave (b) What is its maximum magnetic field strength?arrow_forward
- A microwave source produces pulses of 20.0-GHz radiation, with each pulse lasting 1.00 ns. A parabolic reflector with a face area of radius 6.00 cm is used to focus the micro-waves into a parallel beam of radiation as shown in Figure P24.72. The average power during each pulse is 25.0 kW. (a) What is the wavelength of these microwaves? (b) What is the total energy contained in each pulse? (c) Compute the average energy density inside each pulse. (d) Determine the amplitude of the electric and magnetic fields in these microwaves. (e) Assuming that this pulsed beam strikes an absorbing surface, compute the force exerted on the surface during the 1.00-ns duration of each pulse.arrow_forward(a) What is the intensity of a laser beam used to burn away cancerous tissue that, when 90.0% absorbed, puts 500 J of energy into a circular spot 2.00 mm in diameter in 4.00 s? (b) Discuss how this intensity compares to the average intensity of sunlight (about) and the implications that would have if the laser beam entered your eye. Note how your answer depends on the time duration of the exposure.arrow_forward(a) The ideal size (most efficient) for a broadcast antenna with one end on the ground is one-fourth the wavelength (/4) of the electromagnetic radiation being sent out. If a new radio station has such an antenna that is 50.0 m high, what frequency does it broadcast most efficiently? Is this in the AM or FM band? (b) Discuss the analogy of the fundamental resonant mode of an air column closed at one end to the resonance of currents on an antenna that is one-fourth their wavelength.arrow_forward
- 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?arrow_forwardAssume the radiation from a heat lamp is monochromatic, with a wavelength of 1.5 μm . I =3.313 kW/m^2. a. What is the peak electric field strength, in kilovolts per meter? b. Find the peak magnetic field strength, in microtesla. c. How long, in seconds, will it take to increase the temperature of the 3.95-kg shoulder by 2.00°C, assuming that the shoulder absorbs all the radiation from the lamp and given that its specific heat is 3.47 × 103 J/(kg⋅°C)?arrow_forwardA radio antenna broadcasts a 1.0 MHz radio wave with 26.0 kW of power. Assume that the radiation is emitted uniformly in all directions. a. What is the wave's intensity 30.0 km from the antenna? b. What is the electric field amplitude at this distance?arrow_forward
- a. Write down an E(z,t) and a B(z,t) travelling wave of an EM wave in terms of k and w. What are these constants and the speed of the wave in terms of the wavelength A and the frequency f of the wave? b. What are the energy densities stored in an electric and a magnetic field? c. What is the total instantaneous energy stored per unit volume in a region of space where there is an EM wave? Seeing that that e = express this in terms of the B- field. d. Express the Poynting vector in terms of the B- field. e. What is the time averaged Poynting vector in terms of Eo or Bo (in terms of Ems or Bms). What is the intensity / of the wave?arrow_forwardLight has a frequency of 7.21 × 1013 hertz. What is its wavelength? The speed of light is 3.00 × 108 m/s. a. 2.40 × 10−4 nm b. 2.40 × 105 nm c. 2.16 × 109 nm d. 4.16 × 103 nm e. 4.16 × 10−6 nmarrow_forwardBiologists use optical tweezers to manipulate micron-sized objects using a beam of light. In this technique, a laser beam is focused to a very small-diameter spot. Because small particles are attracted to regions of high light intensity, the focused beam can be used to “grab” onto particles and manipulate them for various experiments. In one experiment, a 10 mW laser beam is focused to a spot that has a diameter of 0.62 μm.a. What is the intensity of the light in this spot?b. What is the amplitude of the electric field?arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University
- Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning