Concept explainers
(a)
The wavelengths that lies in the range of
(a)
Answer to Problem 15P
The wavelength that lie in the range of
Explanation of Solution
Write the expression for the Rydberg’s equation.
Here,
The number corresponding to the Paschen series of hydrogen spectrum is
Conclusion:
For Paschen series:
Substitute
Substitute
Substitute
Substitute
Substitute
Thus, the wavelength that lie in the range of
(b)
The reason for the visibility of the only three wavelengths by the detector.
(b)
Answer to Problem 15P
The three wavelengths are detected by the detector because the detector is moving away from the source and other wavelength is not visible for the detector.
Explanation of Solution
The wavelengths lying in the visible region are the four wavelengths that should be detected by the detector used. Since the detector is moving away from the source, there is a possibility that the higher wavelengths might have undergone red shift.
Due to red shift, the wavelength would have increased and might have gone out of the visible range of the
Conclusion:
Thus, the three wavelengths are detected by the detector because the detector is moving away from the source and other wavelength is not visible for the detector.
(c)
The speed of the stellar object that emits the spectrum.
(c)
Answer to Problem 15P
The speed of the moving stellar object is
Explanation of Solution
Write the expression for the relation between the observed wavelength and the wavelength from the source.
Simplify and rearrange the above expression for
Here,
Write the expression for the speed of the stellar object.
Here,
Conclusion:
Substitute
Substitute
Thus, the speed of the moving stellar object is
Want to see more full solutions like this?
Chapter 3 Solutions
Modern Physics for Scientists and Engineers
- What will be the energy associated with a blue photon (in electronvolts, eV), if the frequency of the blue light is 650 THz (Terahertz (THz); 1 Tera = 1012)? [Hint: Use Planck's equation: E - hf to calculate the photon energy! h- Planck's constant – 6.63 x 10-34 Js = 4.14 x1015 eVs] A. 6.5 eV B. 6.5×10-3 eV C. 2.7 eV D. 2.7×10-27eV E. 2.7x107 eVarrow_forwardThe star Betelgeuse has surface temperature 3590 K and can be regarded as a blackbody. (a) Find the wavelength at which Betelgeuse emits most strongly. Is this visible, ultraviolet, or infrared? (b) Find the amount of power radiated per unit area of the surface of Betelgeuse.arrow_forwardThe bright star Sirius A has a diameter 1.6 times the sun’s and surface temperature 9600 K. (a) What is the peak wavelength of radiation emitted from the surface? (Note: Sirius has a distinctive blue tint when viewed with the naked eye.) (b) Find the net power output from the surface of Sirius A and compare with that from the sun.arrow_forward
- The temperature of a star is 4990 K. Calculate the power per unit area radiated by the star in 519 nm to 525 nm range. (a) 0.230 MW/m (b) 0.384 MW/m (c) 0.390 MW/m2 (d) 0.220 MW/m2arrow_forwardWhat will be the energy associated with a blue photon (in Joules), if the frequency of the blue light is 650 THz (Terahertz (THz); 1 Tera – 1012y? [Hint: Use Planck's cquation: E = hf to calculate the photon energy! h - Planck's constant – 6,63 × 10-4 Js – 4.14 ×1015 eVs] A. 650×1012 J B. 6.5×10° J C. 4.3x1015 J D. 4.3×10-19 J E. 4.3x1019 Jarrow_forwardThe elliptical galaxy NGC 4889 is the largest galaxy in the Coma Cluster (shown in the image below taken by the Hubble Space Telescope). After analyzing the spectrum of NGC 4889, an astronomer identifies a spectral line as being CaII (singly ionized Calcium) with a measured wavelength of 401.8 nm. The true, rest wavelength of this spectral line, measured in a lab, is 393.3 nm. a) What would be this galaxy’s recessional velocity, in km/s? b) Using a Hubble constant of ?0 = 70 km/s/Mpc, find the distance to this galaxy cluster. Give your answer in megaparsecs and in light-years. c) How would your answer to part b) differ if the Hubble constant had a smaller value? A larger value? Explain.arrow_forward
- What is the wavelength in micrometers of peak emission for a black body at 33.5°C? (c = 3.0 × 108 m/s, Wien displacement law constant is 2.9 × 10-3 m ∙ K, σ = 5.67 × 10-8 W/m2 ∙ K4). Please give your answer with one decimal place.arrow_forwardSuppose that a detector in the Hubble Space Telescope was capable of detecting visible light in the wavelength range of 400 to 700 nm. (a) List all the wavelengths for the hydrogen atom that are in this range and their series name. (b) The detector measures visible wavelengths of 537.5 nm, 480.1 nm, and 453.4 nm that researchers believe are due to the hydrogen atom. Why are all the known visible hydrogen lines not detected? (c) Use these data to calculate the speed of the stellar object that emitted the spectra. Assume that the object is not rotating. Why might rotation be an issue?arrow_forwardSuppose a detector in a new space telescope will be capable of detecting visible light between wavelengths 400 nm and 700 nm. List all the wavelengths for the hydrogen atom that are in this range, includingthe upper and lower orbital number for each wavelength.arrow_forward
- A mole contains 6.02 * 1023 particles (atoms, molecules, etc.). If you wanted to reach Alpha Centauri (4.367 light-years away) by creating a strand of carbon atoms (0.3 nm diameter), how many moles of carbon would you need? (Note: 1 light-year = 9.46 * 1012km)arrow_forwardThe radius of a star is 6.95 x 10^8 m, and it's rate of radiation has been measured to be 5.32 x 10^26 W. Assuming that it is a perfect emitter, what is the temperature of the surface of this star? (sigma = 5.67 x 10^-8 W/m^2 . K^4)arrow_forward10-3 W). A laser pointer with a wavelength λ = 550 nm has an output power of 5.80 mW (1 mW = What is the laser pointer's output in photons per second? Recall that Planck's constant is h = 6.63 x 10-34 Js. n = sec ond To use scientific (exponential) notation for your answer, express it using "E". For example, 1.23 x 1014 is entered as 1.23E14.arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningUniversity Physics (14th Edition)PhysicsISBN:9780133969290Author:Hugh D. Young, Roger A. FreedmanPublisher:PEARSONIntroduction To Quantum MechanicsPhysicsISBN:9781107189638Author:Griffiths, David J., Schroeter, Darrell F.Publisher:Cambridge University Press
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningLecture- Tutorials for Introductory AstronomyPhysicsISBN:9780321820464Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina BrissendenPublisher:Addison-WesleyCollege Physics: A Strategic Approach (4th Editio...PhysicsISBN:9780134609034Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart FieldPublisher:PEARSON