Introduction To Health Physics
5th Edition
ISBN: 9780071835275
Author: Johnson, Thomas E. (thomas Edward), Cember, Herman.
Publisher: Mcgraw-hill Education,
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Question
Chapter 14, Problem 14.32P
To determine
The energy of an individual 270-nm photon, in joules, erg and electron volts.
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A dental X-ray typically affects 194 g of tissue and delivers about 3.6 µJ of energy using X-rays that have wavelengths of
0.025 nm.
What is the energy Ephoton, in electron volts, of X-ray photons?
eV
Ephoton =
How many photons are absorbed during the dental X-ray? Assume the body absorbs all of the incident X-rays.
photons
number of photons absorbed:
Problem 10: We observe photons of light coming from a bright star in the night sky. One of those photons has a frequency 6.9 x 10¹4 Hz (or cycles per second).
DS What is the energy of the photon in joules?
Energy -
A photon energy E = 1.00 MeV incident on a detector is
distributed in the direction forming an angle of 60
degrees from its initial direction with energy E' equal t
o.
A. 1.00 MeV
B. 0.502 MeV
C. 1.502 MeV
O D. 1.140 MeV
O E. 9.900 MeV
Chapter 14 Solutions
Introduction To Health Physics
Ch. 14 - Prob. 14.11PCh. 14 - Calculate the gain of a 30-cm-diameter parabolic...Ch. 14 - Prob. 14.13PCh. 14 - Prob. 14.14PCh. 14 - What is the maximum magnetic intensity in a plane...Ch. 14 - Prob. 14.16PCh. 14 - A rectangular horn antenna, 17cm24cm and operating...Ch. 14 - Prob. 14.18PCh. 14 - Prob. 14.19PCh. 14 - Prob. 14.20P
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- A limitation on how many spectra per second can be recorded by a time-of-flight mass spectrometer is the time it takes the slowest ion to go from the source to the detector. Suppose we want to scan up to m/z 500 for ions with z = 1. Calculate the speed of this heaviest ion if it is accelerated through 5.00 kV in the source. How long would it take to drift 2.00 m through a spectrometer? At what frequency could you record spectra if a new extraction cycle were begun each time the heaviest ion reached the detector? What would be the frequency if you wanted to scan up to m/z 1000?arrow_forwardExposure to a sufficient quantity of ultraviolet light will redden the skin, producing erythema—a sunburn. The amount of exposure necessary to produce this reddening depends on the wavelength. For a 1.0 cm2 patch of skin, 3.7 mJ of ultraviolet light at a wavelength of 254 nm will produce reddening; at 300 nm wavelength, 13 mJ are required.a. What is the photon energy corresponding to each of these wavelengths?b. How many total photons does each of these exposures correspond to?c. Explain why there is a difference in the number of photons needed to provoke a response in the two cases.arrow_forwardThe human eye is most sensitive to green light of wavelength 505 nm. Experiments have found that when people are kept in a dark room until their eyes adapt to the darkness, a single photon of green light will trigger receptor cells in the rods of the retina. (a) What is the frequency of this photon? (b) How much energy (in joules and electron volts) does it deliver to the receptor cells? (c) To appreciate what a small amount of energy this is, calculate how fast a typical bacterium of mass 9.5 x 10-12 g would move if it had that much energyarrow_forward
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