CHAPTER 5—X-RAY EQUIPMENT TRUE/FALSE 1. Therapeutic equipment operates at much lower energies than diagnostic equipment. ANS: F DIF: Easy 2. Therapy equipment operates at high voltages and low amperages. ANS: T DIF: Easy 3. Floating tops can be moved when an electromagnetic brake is engaged. ANS: F DIF: Easy 4. The telescoping column of the overhead suspension system controls horizontal movement. ANS: F DIF: Easy 5. A head unit consists of a bucky tray and an x-ray tube. ANS: T DIF: Medium 6. In the United States, the incoming line voltage to an x-ray unit is approximately 120 volts. ANS: F DIF: Easy 7. The root mean square voltage of a single-phase sinusoidal wave is usually given as 70.7% of the peak voltage. ANS: T DIF: Medium 8. During three-phase power, the overall potential difference drops to zero. ANS: F DIF: Easy MULTIPLE CHOICE 1. How many alterations in the direction of the current flow occur per second in a 60-Hz AC current? a. 20 c. 90 b. 60 d. 120 ANS: D DIF: Medium 2. At what point in the x-ray circuit is the rectification circuit located? a. between the semiconductors and the valve tubes b. between the step-down transformer and the rheostat c. between the step-up transformer and the x-ray tube d. between the thermionic diode tubes and the x-ray machines ANS: C DIF: Medium 3. Where is the stator of the anode induction motor located? a. inside the glass envelope but outside the rotor b. outside the glass envelope and outside the rotor c. inside the glass envelope and inside the rotor d. outside the glass envelope but inside the rotor ANS: B DIF: Medium 4. The exposure switch on an x-ray machine is intended to ____. a. initiate the exposure b. terminate the exposure c. both initiate and terminate the exposure d. rotate the anode up to speed ANS: A DIF: Medium 5. The exposure switch is found between the ____. a. incoming line and the circuit breaker b. autotransformer and the timer circuit c. exposure switch and the step-up transformer d. incoming line and the step-down transformer ANS: B DIF: Medium 6. The electrical device used to adjust the mA selection is the ____. a. autotransformer c. switch b. stator d. variable resistor ANS: D DIF: Easy 7. The time control is found between the ____. a. incoming line and the exposure switch b. autotransformer and the timer circuit c. exposure switch and the step-up transformer d. incoming line and the step-down transformer ANS: D DIF: Medium 8. The mA control is found between the ____. a. incoming line and the exposure switch b. autotransformer and the timer circuit c. exposure switch and the step-up transformer d. incoming line and the step-down transformer ANS: D DIF: Medium 9. The kVp control is found between the ____. a. incoming line and the exposure switch b. autotransformer and the timer circuit c. exposure switch and the step-up transformer d. incoming line and the step-down transformer ANS: A DIF: Medium 10. Medical x-ray units can be classified as ____. a. diagnostic b. therapeutic ANS: D c. fluoroscopic d. both a and b DIF: Easy 11. The diagnostic x-ray range is approximately ____. a. 10 to 1,200 mA c. 25 to 150 kVp b. 0.001 to 10 seconds d. all of the above ANS: D DIF: Easy 12. The advantage of a curved top radiographic table is ____. a. positioning accuracy in oblique and lateral positions b. level support of the radiographic film c. easy clean up d. a smaller object image distance ANS: D DIF: Medium 13. The Bucky tray consists of ____. a. a moving 14 × 17 inch grid b. a stationary 14 × 17 inch grid ANS: C DIF: Medium 14. Radiographic table tops may be ____. a. floating b. stationary ANS: D c. a moving 17 × 17 inch grid d. a stationary 17 × 17 inch grid c. motor driven d. all of the above DIF: Medium 15. Radiographic rooms equipped with a tilting table are primarily designed for performing ____ procedures. a. diagnostic c. fluoroscopic b. angiographic d. both a and c ANS: D DIF: Easy 16. The height of the average radiographic table top to the floor is ____ inches. a. 25 c. 60 b. 40 d. 120 ANS: B DIF: Easy 17. Tube suspension systems include ____. a. overhead b. mobile ANS: D c. C-arm d. all of the above DIF: Medium 18. Which tube suspension system offers the greatest multidirectional movement? a. overhead tube suspension system c. floor tube suspension system b. floor-to-ceiling tube suspension system d. mobile tube suspension system ANS: A DIF: Medium 19. The incoming line current is supplied ____. a. b. c. d. in the form of a three-phase power cycle in the form of a single-phase power cycle as a direct current at approximately 60 volts ANS: A DIF: Easy 20. Nearly all x-ray equipment operates from an incoming line of ____. a. 210 V c. 120 Hz b. 120 AC d. 210 A ANS: A DIF: Easy 21. When full-wave rectification is applied to three-phase current, a ____ ripple is produced. a. wye c. voltage b. star d. delta ANS: C DIF: Medium 22. A three-phase, rectified current produces a voltage ripple of ____ pulses per Hz. a. 3 c. 9 b. 6 d. 24 ANS: B DIF: Medium 23. A star or delta connection is used to ____. a. tap a single phase of power b. combine three-phase current ANS: B c. produce rectification d. drop the wave peak to zero DIF: Medium PROBLEM 1. What is the approximate rms voltage of a single-phase sine wave with a kVp of 65? ANS: 45.9 kVp DIF: Difficult 2. What is the approximate rms voltage of a single-phase sine wave with a kVp of 75? ANS: 53.0 kVp DIF: Difficult 3. What is the approximate rms voltage of a single-phase sine wave with a kVp of 80? ANS: 56.6 kVp DIF: Difficult