The Arecibo radio telescope in Puerto Rico can detect a radio wave with an intensity as low as 1 × 10−23 W/m2. As a “best-case” scenario for communication with extraterrestrials. consider the following: suppose an advanced civilization located at point A. a distance x away from Earth, is somehow able to harness the entire power output of a Sun-like star, converting that power completely into a radio-wave signal which is transmitted uniformly in all directions from A. (a) In order for Arecibo to detect this radio signal, what is the maximum value for x in light-years (1 ly ≈ 1016 m)? (b) How does this maximum value compare with the 100,000-ly size of our Milky Way galaxy? The intensity of sunlight at Earth’s orbital distance from the Sun is 1350 W/m2.
Want to see the full answer?
Check out a sample textbook solutionChapter 31 Solutions
Physics for Scientists and Engineers (Chaps 1-38)
Additional Science Textbook Solutions
University Physics Volume 1
Essential University Physics: Volume 1 (3rd Edition)
Tutorials in Introductory Physics
University Physics with Modern Physics (14th Edition)
Essential University Physics (3rd Edition)
Cosmic Perspective Fundamentals
- Radio 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_forward(a) The ideal size (most efficient) for a broadcast antenna with one end on the ground is onefourth 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_forwardIn a region of space where gravitational forces can be neglected, a sphere is accelerated by a uniform light beam of intensity 6.0 mW/m2.The sphere is totally absorbing and has a radius of 2.0 mm and a uniform density of 5.0 * 10^3 kg/m3.What is the magnitude of the sphere’s acceleration due to the light?arrow_forward
- A uniform beam of laser light has a circular cross section of diameter d = 7.5 mm. The beam’s power is P = 4.9 mW. (a) Calculate the intensity, I, of the beam in units of W / m2. (b) The laser beam is incident on a material that completely absorbs the radiation. How much energy, ΔU, in joules, is delivered to the material during a time interval of Δt = 0.89 s? (c) Use the intensity of the beam, I, to calculate the amplitude of the electric field, E0, in volts per meter. (d) Calculate the amplitude of the magnetic field, B0, in teslas.arrow_forwardWhat is the wavelength of the electromagnetic wave emitted by the oscillator–antenna system if L= 0.253 mH and C = 25.0 pF?arrow_forwardA space probe which is a distance of 2.6×1010 mm from a star measures the total intensity of electromagnetic radiation from the star to be 5300 W/m^2 . If the star radiates uniformly in all directions, what is its total average power output?arrow_forward
- Project Seafarer was an ambitious program to construct an enormous antenna, buried underground on a site about 10 000 km2 in area. Its purpose was to transmit signals to submarines while they were deeply submerged. If the effective wavelength were 1.0 * 10^4 Earth radii, what would be the (a) frequency and (b) period of the radiations emitted? Ordinarily, electromagnetic radiations do not penetrate very far into conductors such as seawater, and so normal signals cannot reach the submarines.arrow_forwardProject Seafarer was an ambitious program to construct an enormous antenna, buried underground on a site about 10000 km2 in area. Its purpose was to transmit signals to submarines while they were deeply submerged. If the effective wavelength were 4.6 × 104 Earth radii, what would be the (a) frequency and (b) period of the radiation emitted? Ordinarily, electromagnetic radiations do not penetrate very far into conductors such as seawater. Take the Earth's radius to be 6370 km.arrow_forwardA signal from of PLDT-Fibr travels through its optic cable at the speed of (2x108 m/s).a.) How long will it take for the signal to travel from our house to LJ’s house which has a30.35 km distance b.) What length in inches of the optic cable represents 0.75 ms(millisecond)?arrow_forward
- Remember the wave equation is v = lambda For electromagnetic waves traveling in a vacuum, they all travel at the speed of light =c=2.998*10^ 3 sin A water wave (a mechanical wave, not an electromagnetic wavelhas a frequency of 20 Hz and a wavelength of 0.1 m. Calculate the speed of this wave 8m/s 6 m/s 1/2m/s 4 m/sarrow_forwardThe star Sirius is much hotter than the sun, with a peak wavelength of 290 nm compared to the sun’s 500 nm. It is also larger, with a diameter 1.7 times that of the sun. By what factor does the energy emitted by Sirius exceed that of the sun?arrow_forwardAt the top of Earth’s atmosphere, the time-averaged Poynting vector associated with sunlight has a magnitude of about 1.49 kW/m2. a. What is the maximum value for the electric field of a wave of this intensity? Give your answer in volts per meter. b. What is the maximum value for the magnetic field of a wave of this intensity? Give your answer in teslas. c. What is the total power radiated by the sun? Assume that the Earth is 1.5×10111.5×1011 m from the Sun and that sunlight is composed of electromagnetic plane waves. Give your answer in watts.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 Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill