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Conceptual questions

Why is a PET scan more accurate than a SPECT scan?

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Isotopes that emit α radiation are relatively safe outside the body and exceptionally hazardous inside. Explain why.

Alpha particles do not penetrate materials such as skin and clothes easily. (Recall that alpha radiation is barely able to pass through a thin sheet of paper.) However, when produce inside the body, neighboring cells are vulnerable.

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Ionizing radiation can impair the ability of a cell to repair DNA. What are the three ways the cell can respond?

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Problems

What is the dose in mSv for: (a) a 0.1-Gy X-ray? (b) 2.5 mGy of neutron exposure to the eye? (c) 1.5m Gy of α exposure?

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Find the radiation dose in Gy for: (a) A 10-mSv fluoroscopic X-ray series. (b) 50 mSv of skin exposure by an α emitter. (c) 160 mSv of β and γ rays from the 40 K in your body.

Gy = Sv RBE : a. 0.01 Gy; b. 0.0025 Gy; c. 0.16 Gy

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Find the mass of 239 P u that has an activity of 1.00 μCi .

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In the 1980s, the term picowave was used to describe food irradiation in order to overcome public resistance by playing on the well-known safety of microwave radiation. Find the energy in MeV of a photon having a wavelength of a picometer.

1.24 MeV

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What is the dose in Sv in a cancer treatment that exposes the patient to 200 Gy of γ rays?

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One half the γ rays from 99 m T c are absorbed by a 0.170-mm-thick lead shielding. Half of the γ rays that pass through the first layer of lead are absorbed in a second layer of equal thickness. What thickness of lead will absorb all but one in 1000 of these γ rays?

1.69 mm

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How many Gy of exposure is needed to give a cancerous tumor a dose of 40 Sv if it is exposed to α activity?

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A plumber at a nuclear power plant receives a whole-body dose of 30 mSv in 15 minutes while repairing a crucial valve. Find the radiation-induced yearly risk of death from cancer and the chance of genetic defect from this maximum allowable exposure.

For cancer: ( 3 rem ) ( 10 10 6 rem · y ) = 30 10 6 y , The risk each year of dying from induced cancer is 30 in a million. For genetic defect: ( 3 rem ) ( 3.3 10 6 rem · y ) = 9.9 10 6 y , The chance each year of an induced genetic defect is 10 in a million.

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Calculate the dose in rem/y for the lungs of a weapons plant employee who inhales and retains an activity of 1.00 μ Ci 239 Pu in an accident. The mass of affected lung tissue is 2.00 kg and the plutonium decays by emission of a 5.23-MeV α particle. Assume a RBE value of 20.

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Additional problems

The wiki-phony site states that the atomic mass of chlorine is 40 g/mol. Check this result. Hint: The two, most common stable isotopes of chlorine are: 17 35 Cl and 17 37 Cl . (The abundance of Cl-35 is 75.8 % , and the abundance of Cl-37 is 24.2 % .)

atomic mass ( Cl ) = 35.5 g/mol

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A particle physicist discovers a neutral particle with a mass of 2.02733 u that he assumes is two neutrons bound together.

(a) Find the binding energy.

(b) What is unreasonable about this result?

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A nuclear physicist finds 1.0 μ g of 236 U in a piece of uranium ore ( T 1/2 = 2.348 × 10 7 y ). (a) Use the decay law to determine how much 236 U would had to have been on Earth when it formed 4.543 × 10 9 y ago for 1.0 μ g to be left today. (b) What is unreasonable about this result? (c) How is this unreasonable result resolved?

a. 1.71 × 10 58 kg ; b. This mass is impossibly large; it is greater than the mass of the entire Milky Way galaxy. c. 236 U is not produced through natural processes operating over long times on Earth, but through artificial processes in a nuclear reactor.

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Questions & Answers

what is electro statics
fitsum Reply
when you consider systems consisting of fixed charges
Sherly
Diagram of the derive rotational analog equation of v= u+at
Nnamnso Reply
what is carat
Arnulfo Reply
what is chemistry
Mrs Reply
what chemistry ?
Abakar
where are the mcq
Fred Reply
ok
Giorgi
acids and bases
Navya
How does unpolarized light have electric vector randomly oriented in all directions.
Tanishq Reply
unpolarized light refers to a wave collection which has an equal distribution of electric field orientations for all directions
pro
In a grating, the angle of diffraction for second order maximum is 30°.When light of wavelength 5*10^-10cm is used. Calculate the number of lines per cm of the grating.
Micheal Reply
state the law of gravity 6
cletus Reply
what is cathodic protection
Ebe Reply
its just a technique used for the protection of a metal from corrosion by making it cathode of an electrochemical cell.
akif
what is interferometer
Sonu Reply
what is interferometer
Abakar
Show that n1Sino1=n2Sino2
javan Reply
what's propagation
Vikas Reply
is it in context of waves?
Edgar
It is the manner of motion of the energy whether mechanical(requiring elastic medium)or electromagnetic(non interference with medium)
Edgar
determine displacement cat any time t for a body of mass 2kg under a time varrying force ft=bt³+csinkt
Felix Reply
A round diaphragm S with diameter of d = 0.05 is used as light source in Michelson interferometer shown on the picture. The diaphragm is illuminated by parallel beam of monochromatic light with wavelength of λ = 0.6 μm. The distances are A B = 30, A C = 10 . The interference picture is in the form of concentric circles and is observed on the screen placed in the focal plane of the lens. Estimate the number of interference rings m observed near the main diffractive maximum.
Jyoti Reply
A Pb wire wound in a tight solenoid of diameter of 4.0 mm is cooled to a temperature of 5.0 K. The wire is connected in series with a 50-Ωresistor and a variable source of emf. As the emf is increased, what value does it have when the superconductivity of the wire is destroyed?
Rupal Reply

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Source:  OpenStax, University physics volume 3. OpenStax CNX. Nov 04, 2016 Download for free at http://cnx.org/content/col12067/1.4
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