Rad Review Questions Worksheet

Question 1

The formula for determining the heat units for a 3-phase, 6-pulse x-ray generator is

Answer 1

kV x Time x mA x 1.35

Question 2

The voltmeter, which reads the kVp selected, is located where in the radiographic circuit?

Answer 2

between the auto xfmr. & step-up xfmr.

Question 3

How many rectifiers are required for a full-wave, 3-phase, 12-pulse x-ray generator?

Answer 3

twelve

Question 4

During fluoroscopy, what is the range of mA used in the x-ray tube?

Answer 4

0.5-5 mA

Question 5

An exposure is taken with a spinning top on a single-phase, fully rectified x-ray generator at an exposure time of 1/30 sec. If the timer circuit is working properly, the radiograph should yield

Answer 5

4 dots

Question 6

Why is it important for the x-ray tube to have a vacuum inside it?

Answer 6

this allows electrons to flow without any impedance

Question 7

A tube rating chart is used to

Answer 7

provide a safe range of exposure factors that may be utilized

Question 8

Which of the following methods are used to regulate the amount of thermionic emission that occurs at the filament?

Answer 8

variable resistor

Question 9

How long does it take for the completion of one sine wave representing 60 hertz of current?

Answer 9

1/60 second

Question 10

According to the law of conservation of energy, voltage and amperage have which type of relationship across a transformer?

Answer 10

inversely proportional to each other

Question 11

In the image intensifier, the anode serves to

Answer 11

accelerate the electrons across the tube

Question 12

What component in the image intensifier allows images to be magnified?

Answer 12

electrostatic focusing lens

Question 13

The inverse square law relationship between intensity and distance from a source is based upon

Answer 13

divergence

Question 14

Photomultipliers, thyratrons, and ionization chambers are devices used in

Answer 14

automatic exposure devices

Question 15

The size of an object is 7”. The SID is 40”. The OID is 9”. What is the resultant size of the image?

Answer 15

9.03”

Question 16

When electrons approach the positive electrostatic field of the target, they are abruptly decelerated and lose energy. This energy is converted to

Answer 16

Bremsstrahlung radiation

Question 17

In the usual diagnostic KV range, insofar as energy absorption from the beam is concerned, which type of interaction between radiation and matter predominates?

Answer 17

photoelectric effect

Question 18

In the x-ray circuit, the current flowing between the rectifier and the tube is

Answer 18

pulsating DC

Question 19

As radiation enters the body, two effects can occur: it can be attenuated or it can penetrate completely through. Which of the following is not a factor affecting attenuation?

Answer 19

X-rays are electrically neutral

Question 20

Which of the following statements is/are correct regarding the anode?
I. It is the positive pole
II. The electron cloud forms here
III. It may be stationary or rotating

Answer 20

I and III

Question 21

Minification gain occurs when

Answer 21

electrons from the photocathode converge on the output screen

Question 22

A radiographic unit that requires an oscilloscope to detect voltage waveform irregularities would be

Answer 22

a 3-phase, 12-pulse unit

Question 23

The thickness of the tomographic section is determined by

Answer 23

exposure angle

Question 24

The compton effect is characterized by

Answer 24

. part transfer of energy upon collision

Question 25

Gamma and x-radiation are the same in every way except

Answer 25

both have the same origin

Question 26

The basic reward of the air-gap technique, improved contrast, relies on the following principle

Answer 26

due to increased OID, the angle of the scatter will miss the film

Question 27

The M shell orbit in atomic formation is able to contain a maximum of

Answer 27

18 electrons

Question 28

X-rays produced from the movement of electrons from an outer shell to an inner shell is termed

Answer 28

characteristic radiation

Question 29

What is the efficiency of x-ray production, using a tungsten anode, at 90 KVp?

Answer 29

0.675%

Question 30

Faraday’s Law is also referred to as the

Answer 30

Law of Electromagnetic Induction

Question 31

During a fluoroscopic procedure, the radiologist selects a smaller field-of-view, resulting in a magnified image on the TV monitor. How does this affect the amount of radiation that the patient receives?

Answer 31

it increases the amount of radiation the patient receives

Question 32

The incident photon gives up all its energy to cause excitation; a new photon of the same energy is given off in a random direction

Answer 32

Unmodified Scatter

Question 33

Produces an ion pair.

Answer 33

Photoelectric and Compton Scatter

Question 34

Is responsible for true absorption.

Answer 34

Photoelectric Effect

Question 35

Is responsible for scattered radiation causing fogged film

Answer 35

Compton Scatter

Question 36

Causes ionization in tissue

Answer 36

Photoelectric Effect and Compton Scatter

Question 37

Incident photon with KeV greater than but close to the binding energy of inner shell electron. Atomic # is high to increase probability

Answer 37

Photoelectric Effect

Question 38

Incident photon with KeV considerably greater than the binding energy of outer shell electrons.

Answer 38

Compton Scatter

Question 39

Results in true secondary radiation and energies characteristic of the binding energies of the shells involved

Answer 39

Photoelectric Effect