超星 - 专业英语自测

单选题

X-rays _____.

A. always travel in a straight line
B. can be influenced by an electrical field
C. are absorbed equally by the materials they pass through
D. None of the above

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单选题

Bremsstrahlung production of X-rays produces radiation that is composed of ____.

A. a small number of very defined energies
B. a continuous spectrum of energies over some range
C. radiation of only one energy
D. none of the above

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单选题

Which of the following is required to produce an x-ray?

A source of electrons
B. A large potential difference
C. A vacuum
D. All the above

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单选题

Most of the energy of the electrons from the cathode is converted to _____.

A. X-rays
B. Scatter
C. Heat
D. primary beam

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单选题

Upon completing an X-ray exposure and turning the equipment off, _____.

A. personnel should wait for a few minutes before entering the exposure area.
B. personnel should wear a lead-lined apron before entering-the exposure area.
C. personnel should enter the exposure area without fear of radiation exposure.
D. personnel should take a reading with a survey meter before entering the exposure area.

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单选题

Characteristic X-ray radiation provides the spectrums as followings except

A. Characteristic X-ray radiation is a discrete emission spectrum.
B. Characteristic X-ray radiation changes its energy when tube voltage varies.
C. Given the same amount of electron flow, a high tube voltage grants higher X-ray intensity.
D. In mammography over 80% radiation is caused by characteristic radiation.

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单选题

The ratio of heat produced to x-rays produced in a typical diagnostic target is about

A. 1:99
B. 10:90
C. 50:50
D. 99:1

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单选题

Which of the following description on bremsstrahlung radiation is not correct?

A. Bremsstrahlung radiation has a broad energy distribution, with the greatest number of x rays being produced at the low energies.
B. The general shape of the bremsstrahlung radiation is different for all x-ray imaging systems.
C. The maximum energy (in keV) of a bremsstrahlung x-ray is numerically equal to the kVp operation.
D. The greatest number of x-rays is emitted with energy approximately one third of the maximum energy.

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单选题

German physicist, Wilhelm Roentgen, discovered the X-ray in 1895. What was the first human body part he tried to image?

A. Head
B. Hand
Chest
D. Foot

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单选题

Thermionic emission is electrons being boiled off and creates something called ____.

A. Space emissions
B. Static charge
C. Space charge
D. X-ray

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