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WorksheetsAttenuation and Impedance
Total questions: 35
Worksheet time: 19mins
The decrease in strength of a sound wave as it travels
Prop Speed
Frequency
Attenuation
Attenuations relation to speed
Directly
Inversely
Not related
3 components of attenuation
Absorption
Scattering
Reflection
Refration
Less attenuation =
Shorter distance
Longer distance
Less attenuation =
Lower frequency
Higher frequency
More attenuation =
Short distance
Longer distance
More attenuation =
Low frequency
High frequency
What is used to remove air from the path of ultrasound?
Saline
Gel
Water
Powder
Which of the following is related to greater attenuation?
Long distance, low frequency
Long distance, high frequency
Short distance, low frequency
Short distance, high frequency
Which of the following results in the wave with the highest intensity?
Long distance, low frequency
Long distance, high frequency
Short distance, low frequency
Short distance, high frequency
Which of the following results in the least attenuation?
4 Mhz, 2cm
4 MHz, 8 cm
6 MHz, 8 cm
6 MHz, 4 cm
Which of the following results in the most attenuation?
4 MHz, 2 cm
4 MHz, 8 cm
6 MHz, 8 cm
6 MHz, 4 cm
Reflections from a smooth reflector are
Specular
Diffuse
Backscatter is another word for
Specular
Rough
Diffuse
Smooth
As frequency increases, scattering
Increases
Decreases
Remains the same
Stronger reflections are produced with
Normal Incidence
90 degrees
60 degrees
As frequency increases, the attenuation coefficient
Increases
Decreases
Remains the Same
Attenuation coefficient is __ of the transducers frequency
1/4
1/2
1/3
2/3
The unit for impedance is
Watts/cm
Pascals
Rayls
Hz
Impedance is (a) not measured
Which of the 3 components of attenuation is the dominant contributor?
Absorption
Reflection
Scattering
As the path length increases, attenuation of US in soft tissue
Increases
Decreases
Remains the Same
Attenuation in soft tissue is related to_____ & _____
Path Length
Frequency
Sound
Scattering
Attenuation in lung tissue is ____ soft tissue
Less Than
Greater Than
Equal To
Attenuation in bone is____ soft tissue
Greater than
Less than
Equal to
Attenuation in air is ____soft tissue
Greater than
Less than
Equal to
Attenuation in water is _____ soft tissue
Greater than
Less than
Equal to
What are the units of attenuation?
dB
Pascals
Watts/cm
What is the relationship between US frequency and the attenuation coefficient in soft tissue?
Half
Double
Equal
As the path length increases, the attenuation coefficient of US in soft tissue
Increases
Decreases
Remains the same
Impedance is important in _____ at boundaries
Reflections
Refractions
Absorptions
Scatterings
Which is better to use while examining a carotid artery?
7.5 MHz
3 MHz
In soft tissue, attenuation coefficient is directly related to
(a)
The amount of Rayleigh scattering is related to _____ and increases by a factor of
16
Frequency
8
Prop speed
Rayleigh scattering means that the sound scatters in ____ & ____
Uniform
All directions
One direction
Not uniform
