Chapter 3: the Dental Xray Machine

c

Dental x-ray machines contain each of the following components except one. Which one is the exception?

a. Control panel

b. Extension arm

c. Radioactive material

d. Tube head

d

Which regulating device on the control panel measures the amount of current passing through the wires of the circuit?

a. Timer

b. Line switch

c. kVp selector

d. mA selector

b

Each of the following conditions must exist for x-rays to be produced except one. Which one is the exception?

a. A target capable of stopping the electrons

b. An air-filled glass tube

c. High voltage to impart speed on the electrons

d. A source of free electrons

a

Which of the following is not function of the tube head?

a. It allows all radiation to exit

b. It provides grouding for the electrical components

c. It protects the x-ray tube from accidental damage

d. It prevents overheating of the x-ray tube

d

The anode is composed of the focusing cup and the filament, AND must be charged negative during x-ray production.

a. The first part of the statement is correct, the second part of the statement is not correct

b. The first part of the statement is not correct, the second part of the statement is correct

c. Both parts of the statement are correct

d. Both parts of the statement are not correct

b

How many electrical circuits are used in a dental x-ray machine?

a. One

b. Two

c. Three

d. Four

d

Sixty (60) impulses is equivalent to...

a. 1/6 second

b. 1/10 second

c. 1/2 second

d. 1 second

a

The intensity of the x-ray beam is affected by each of the following except one. Which one is the exception?

a. Target size

b. Kilovoltage

c. Exposure time

d. Milliamperage

c

Direct (DC) current is best suited for use with digital radiography, AND may produce more consistent exposures at the very short exposure times.

a. The first part of the statement is correct, the second part of the statement is not correct

b. The first part of the statement is not correct, the second part of the statement is correct

c. Both parts of the statement are correct

d. Both parts of the statement are not correct

c

Which of these statements is false?

a. The positive anode and negative cathode are sealed within the x-ray tube.

b. The control panel may be integrated with the x-ray machine tube head support.

c. The exposure button should be on the end of a 3 foot timer cord.

d. The x-ray tube contains a target capable of stopping the electrons.

a

The duration of an x-ray exposure is determined by which control?

a. Timer

b. Line switch

c. kVp selector

d. mA selector

c

The filament and target are made out of tungsten because tungsten...

a. produces fewer electrons

b. prevents electrons from being liberated

c. withstands high temperatures

d. ensures that xrays are projected in one direction

c

Which transformer corrects minor fluctuations in the current flowing through the wires?

a. Step-up transformer

b. Step-down transformer

c. Autotransformer

d

X-rays originate at the...

a. cathode

b. port

c. focusing cup

d. focal spot

b

Amperage measures the electric potential or force that moves electrons along a conductor. Increasing the force with which the electrons move increases the penetrating potential of the x-ray beam.

a. The first statement is true. The second statement is false

b. The first statement is false. The second statement is true

c. Both statements are true

d. Both statements are false

d

Which of the following best describes how x-rays are actually produced in the dental x-ray tube?

a. Radioactive particulate matter undergoes controlled disintegration

b. Electrical current passes through an oil mixture, creating minute explosions

c. Low milliamperage current is transformed into high kilovoltage current

d. High-speed electrons collide with target material electrons

d

What percent of the kinetic energy inside the x-ray tube is actually converted to x-radiation?

a. 99 percent

b. 50 percent

c. 25 percent

d. 1 percent

c

Increasing which of the following would best increase the number of electrons flowing through the dental x-ray electrical circuit?

a. Impulses

b. Kilovoltage

c. Milliamperage

d. PID length

c

Which of the following removes the soft x-rays for the x-ray beam as it exits the port?

a. Position indicating device

b. Collimator

c. Filter

d. Transformer

b

How does the radiographer know when the x-ray exposure cycle is complete?

a. When the dead-mas switch cannot be depressed

b. When the audible beep stops

c. When the timer dial completes the rotation

d. When the indicator light illuminates