1-5
Half-value layer thickness is equal to an intensity reduction of:
3 dB
A sound beam travels 15 cm in soft tissue. The attenuation coefficient is 6 dB/cm. What is the total attenuation that the sound beam experienced?
90 dB
The term that defines the acoustic resistance to sound traveling in a medium is described in:
Rayls
The following equation properly describes which of the following coefficients:
Equation: (Z2 - Z1/Z2 + Z1)2 x 100
Incident intensity
Attenuation
Intensity transmission
Intensity reflection
Intensity reflection
Which of the following terms does not belong with the others?
Normal
Orthogonal
Oblique
Perpendicular
Oblique
A scale associated with decibel notation is:
Logarithm
A sound pulse travels in medium 1 and strikes an interface with another tissue, medium 2, at an incident angle of 25 degrees. The angle of transmission is 5 degrees. Refraction has occurred. In which medium does sound travel the slowest? (Image)
Medium 2
What conditions are necessary for refraction to occur at a boundary between two media?
Different propagation speeds and oblique incidence at the boundary
What is a decibel?
A ratio between two numbers
A transducer's output power is adjusted by -12 dB. What does this decibel represent?
1/16
The initial intensity of a wave is 2 mW/cm2, and there is a change of +12 dB. What is the final intensity?
32 mW/cm2
The attenuation coefficient is _____ the frequency.
1/2
Which of the following best pertains to Snell's law?
Reflection with normal incidence
Reflection with oblique incidence
Transmission with normal incidence
Transmission with oblique incidence
Transmission with oblique incidence
Which of the following mathematically describes the physics of refraction?
Snell's Law
Pouiselle's Law
Bernoulli's Law
Murphy's Law
Snell's Law
Which of the following terms best describes a reflection arising from a rough boundary?
Specular
Diffuse
Rayleigh
Normal incidence
Diffuse
The power of a system is at 100%. What is the dB change when the systems power is reduced to 50%?
- 3 dB
What does 3.5 dB/cm represent? (Image)
Attenuation coefficient
As a pulse passes through soft tissue, a certain amount of acoustic energy remains in the tissue as heat. Which attenuation is described?
Absorption
Weakening of a sound wave as it travels through a medium defines:
Attenuation
A sound wave with an intensity of 50W/cm2 strikes the boundary and is completely reflected. What is the intensity reflection coefficient?
100%
Which of the following formulas determines the impedance of a medium?
Propagation speed of the medium multiplied by the round-trip time
Density of the medium multiplied by the attenuation coefficient
Attenuation multiplied by the propagation speed of the medium
Density of the medium multiplied by the propagation speed of the medium
Density of the medium multiplied by the propagation speed of the medium
What do the rayls units represent? (Image)
Medium resistence
A sound wave strikes a boundary with normal incidence. The impedances of the two media are identical. What percentage of the sound wave is reflected?
0%
What specific component of Attenuation is best illustrated? (Image)
The impedance of Medium 1 is 10 rayls. The propagation speed is 1,450 m/s. The impedance of Medium 2 is 8 rayls, and the speed is 1,540 m/s. A sound beam strikes the boundary between the media and is both partially transmitted and reflected. The angle of incidence is 45 degrees. What is the reflected angle?
45 degrees