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Physics U4 & HW
Question | Answer |
---|---|
X-ray wavelength is: | Inversely proportional to frequency |
Which of the following is true about both a 100 keV x-ray and a 10 keV gamma ray? | They have equal wavelengths |
When the frequency of electromagnetic radiation is increased tenfold: | the wavelength decreases to 1/10 |
A single unit of electromagnetic radiation is also called a/an: | Photon |
Light has a constant velocity of c=3x108 m/s Therefore | Its frequency decreases with increasing wavelength |
The frequency of electromagnetic radiation is | measured in hertz |
When one uses the sine wave as a model | the distance from one peak to the next is the wavelength |
Given the sine wave model of electromagnetic radiation | frequency times wavelength is a constant |
Which of the following has a constant value for all electromagnetic radiation | Velocity |
The amplitude of a sine wave is its | Zero to maximum |
The frequency of a sine wave is | the number of valleys that pass per second |
The wave equation is described as follows | Wavelength is velocity divided by frequency |
When the electromagnetic spectrum is considered, photons of a radio broadcast have relative | Low energy and long wavelengths |
The principle difference between x-rays and gamma rays are their | origin |
Radiation emitted from a standard radio broadcast antenna | Is electromagnetic radiation |
For any electromagnetic radiation | An increase in frequency results in an increase in energy |
If an x-ray imaging system is operated at 40 kVp then | 20 keV x-rays will be emitted |
Which of the following characteristics is the same for both ultraviolet radiation and microwaves? | Velocity |
Visible light cannot be | Weighed |
X-rays can be | Attenuated |
The electromagnetic spectrum includes | X-rays and radar with the speed of light in a vacuum |
Which of the following is not a characteristic of the wave model of radiation? | Collision |
Which of the following most closely represents the term attenuation? | light transmitted through frosted glass |
When a radiograph is viewed, one might properly state that | lung tissue is radiolucent |
The development of modern quantum mechanics is attributed to | max Planck |
According to quantum mechanics the energy of an x-ray is | inversely proportional to its wavelength |
Which of the following statements about visible light is true? | It sometimes behaves like a wave |
. Visible light | consists of a shorter wavelength red radiation and long wavelength blue radiation |
Which of the following terms is not associated with visible light interaction? | Vaporization |
Which statement about visible light is correct? | If visible light is transmitted unattenuated the matter is lucent |
In radiographs of bony structures embedded in soft tissue the bone is | radiopaque |
Which of the following statements about photon interaction is true? | Lead is radiopaque |
Which type of electromagnetic radiation is not used for medical imaging? | Microwaves |
When compared with visible light x-rays have greater | frequency |
Which of the following types of electromagnetic radiation interacts with matter such as a particle? | Gamma Ray |
At what level should visible light interact most readily? | Molecular |
A source of99mTe produces a radiation intensity of 150mR/hr. at 10mR. At what distance does the exposure rate equal to 1000mR/hr.? | 3.9 m |
If the exposure rate 1m from a source is 9 mR/hr. what is the exposure rate 3, from the source? | 1 mR/hr. |
The inverse square law states | intensity is inversely proportional to the square of the distance |
The inverse square law is a result of | Divergence |
The inverse square relationship applies to which of the following sources | Point |
Which of the following emissions is likely to obey the inverse square law? | X-rays from mobile imaging unit |
To apply the inverse square law one must know | Two distances and one intensity |
If the distance from a point source is tripled the intensity will be | one ninth |
If an instrument positioned 1m from appoint source is moved 50 cm closer to the source the radiation intensity will be | increased by a factor of 4 |
The distance from the earth to the sun is approximately 150 million km. If the earth were orbiting the sun at 50 million km the solar intensity on the surface of the earth would be | 9 times more intense |
A 137Cs source used from instrument calibration has an intensity of 100mR/hr. at 20 cm. What would the intensity be 40 cm from the source? | 25 mR/hr. |
The exposure rate from a 60Co source used in radiation therapy is 100 mR/hr. at 80 cm. What would be the exposure rate at 40 cm from the source? | 400 R/hr. |
A radiographic technique produces a patient dose of 200 mrad at a source to skin distance of 80 cm. What would the patient dose be at an SSD of 160 cm if the technique remains the same | 50 mrad |
A radiographic technique produces an exposure of 200 mR at a source to image receptor distance of 100 cm. What would the exposure rate be at an SID of 180 cm? | 111 mR |
A radiograph produced at an SID of 100 cm results in an exposure of 100mR. What would be the exposure if the SID were reduced to 90 cm? | 123 mR |
Which of the following terms is associated with diagnostic imaging? | Superficial X-rays |
Which of the following terms does not apply to an x-ray? | Reflection |
Given two x-rays, one of 50keV and the other at 70keV x-ray, the 70 keV has | Has a higher frequency |
In the normal representation of an x-ray | Velocity is the speed of light |
The energy of an x-ray photon is directly proportional to its | Frequency |
Which of the following is greater for a 30 keV x-ray than a 60keV x-ray | Wavelength |
Which of the following electromagnetic radiations is in the diagnostic x-ray region | 65 keV |
When x-rays are described it can be said that | they are deflected by a very strong magnet |
x-ray photons | have a higher frequency than visible light |
The energy of an x-ray | is inversely proportional to its wavelength |
The model used to describe an x-ray photon | is a sine wave |
which of the following characteristic is the same for both x-ray photons and light photons | Velocity is the same |
X-rays | have zero rest mass and neutral velocity |
Diagnostic x-rays are | high energy electromagnetic radiation |
An x-ray can be correctly called a | photon |
4 Properties of a Photon: | 1) Wavelength 2) Frequency 3) Velocity 4) Amplitude |
Define quantum: | Bundle(amount) of energy |
Define x-ray photon: | A quantum of electromagnetic energy |
1/2 the range from crest to valley over which the sine wave varies. | Amplitude |
Where is peak kVp represented on the sine wave? | The very top(crest) of the amplitude portion of the sine wave |
1 cycle = _______ alternations | 2 |
How many cycles in 1 second? | 60 |
How many alternations in 1 second? | 120 |
Where on the sine wave of voltage does voltage measure 0? | the part that intersects the time line (equilibrium) |
The sine wave portion above the time line represents what? | The amplitude |
What direction is the current moving if the sine line is above the time line? Below the time line? | Forward; Backward |
The ____________ is the part of the wave where it extends from 0 (+/-) and returns to 0. | Alternation |
The number of oscillations per second is the ___________________. | Frequency |
y= | Sinθ |
What is frequency; Symbol for frequency and unit of measure: | How often the crest occurs; nu; hertz |
Wavelength is the distance between the ________ of a _________; Symbol is _______; Unit of measure is _________. | Crests of a wave; λ-lambda; Å-Angstrom |
Meaning of λ-min: | Lambda min= Minimum wavelength=strongest photon in the beam of radiation |
What is the relationship between wavelength and frequency: | Inversely proportional |
Formula for the speed of light (C): | C=μλ |
3 Regions for the Electromagnetic Spectrum: | Visible light Radio Frequency x-Radiation |
Electromagetic spectrum from longest wavelength: lowest frequency to shortest wavelength: Highest frequency | Radio frequency Microwaves Infra-red Visible light Ultra Violet Light X-Ray Gamma Cosmic |
When pure energy acts as though it has the characterists of matter: | Wave-Particle Duality Phenomenon |
Term for light deviated from its line of travel: | Refraction |
Substance that absorbs radiation is ___________ and appears __________ on a radiograph. | Radiopaque; clear or light area |
A substance that attenuates radiation is termed ___________ and appears _____________ on a radiograph. | Radiolucent; Dark |
What does the Particle Model: Quantum Theory state: | X-rays are created and exist at the speed of light or dont exist at all. X-rays are directly proportional to frequency |
According to the Particle Model: Quantum Theory, x-rays are directly proportional to what? | Frequency |
What is the Law of Conservation of Energy? | Energy can never be created or destroyed: E=mc² |