test#1 review

Which term describes a beam of radiant energy that has the power to penetrate substances and record images on photographic film?

• Alpha particles

• Beta particles

• Gamma rays

• X-rays

Who is credited with discovering X-rays in 1895?

• Henri Becquerel

• Wilhelm Roentgen

• C. Edmund Kells

• Franklin W. McCormack

Which cells are most radiosensitive?

• Highly specialized, nondividing cells

• Long-lived cells

• Cells with high metabolic activity and division rate

• Mature nerve cells

Which of the following is reflective of a stochastic radiation effect?

• A threshold curve

• Severity of clinical signs independent of dose

• The greater the dose, the greater the clinical effect

• An immediate effect after exposure

Which of the following occurs with the x-ray photon in the photoelectric effect?

• Photon passes through unchanged

• Photon is completely absorbed

• Photon scattered unpredictably

• Photon creates two new particles

Increasing kVp while holding mA and exposure time constant will:

• Darken the film image

• Lighten the film image

• Increase detail

• Have no effect

Which type of transformer is used in a dental x-ray machine to increase the voltage needed to accelerate electrons from the cathode to the anode?

• Step-down transformer

• Autotransformer

• Step-up transformer

• Rectifier transformer

In a dental x-ray tube, what is the function of the molybdenum cup and the tungsten target?

• molybdenum cup focuses electrons; tungsten target produces x-rays

• molybdenum cup produces x-rays; tungsten target focuses electrons

• molybdenum cup and tungsten target focus the x-ray beam

• molybdenum cup prevents overheating; tungsten target filters low-energy photons

Which of the following correctly compares Compton scatter and coherent scatter?

• Compton scatter involves no loss of energy; coherent scatter results in ionization

• Compton and coherent scatter result in ionization

• Compton scatter results in ionization and energy loss; coherent scatter causes no ionization and no energy change

• Compton scatter produces less image contrast than coherent scatter

What is the electron shell that has highest bonding energy and most likely to be involved in photoelectric interactions?

• inner shell

• middle shell

• M-shell

• outer shell