Physics Top 100 Flashcards
If sound waves of 2 MHz, 5 MHz and 7.5 MHz are transmitted through the heart, reflections from which frequency will arrive back to the transducer first?
Reflections from all three frequencies will have identical round trip times
Increasing the frequency will result in all of the following except decrease:
(a) period (b) pulse duration (c) wavelength (d) spatial pulse length (e) beam width (f) beam divergence (g) depth of penetration (h) duty factor (i) attenuation (j) axial resolution-numerically (k) lateral resolution-numerically
(i) attenuation
Decibel(s) are the units for all of the following except:
(a) amplitude (b) transmit gain (c) gain (d) attenuation (e) TGC (f) dynamic range (g) intensity
(g) intensity
Which of the following performs spectral analysis for conventional (PW, CW) Doppler?
(a) autocorrelation
(b) fast Fourier transform
(c) Bernoulli
(d) Huygen
(b) fast Fourier transform
The artifact which will result in an increase in echo amplitude is:
(a) shadowing
(b) enhancement
(c) reverberation
(d) propagation speed error
(b) enhancement
The artifact which may result in the inability to detect mitral regurgitation from the apical views in a patient with a mitral valve replacement is:
(a) enhancement
(b) shadowing
(c) reverberation
(d) side lobe
(b) shadowing
An increase in log compression will (blank) dynamic range.
(a) increase
(b) decrease
(c) not change
(d) cannot be predicted
(a) Increase
An increase in dynamic range will (blank) the number of shades of gray displayed?
(a) increase
(b) decrease
(c) not change
(d) cannot be predicted
(a) increase
Which of the following is not considered mechanical focusing?
(a) internal focusing
(b) external focusing
(c) acoustic lens
(d) receive
(d) receive
The best way to practice ALARA is to:
(a) increase transmit gain
(b) reduce scan time
(c) increase PRF
(d) utilize PW Doppler
(b) reduce scan time
An increase in packet size will (blank) the frame rate.
(a) increase
(b) decrease
(c) not effect
(d) cannot be predicted
(b) decrease
The placement of color flow on moving structures is called:
(a) ghosting- flash artifact
(b) reverberation
(c) grating lobe
(d) shadowing
(a) ghosting- flash artifact
The range for audible sound is:
(a) less than 20 Hz
(b) 20 Hz to 20 kHz
(c) greater than 20 kHz
(d) 2 MHz to 15 MHz
(b) 20 Hz to 20 kHz
The wavelength of a 1.0 MHz transducer is (blank), assuming soft tissue.
(a) 154mm
(b) 15.4 mm
(c) 1.54 mm
(d) .154 mm
(c) 1.54 mm
The AVERAGE speed of sound in soft tissue is:
(a) 1540 m/s
(b) 1.540 m/s
(c) 15.40 m/s
(d) 154.0 m/s
(a) 1540 m/s
How much sound energy is reflected at a soft tissue-air interface?
(a) 1%
(b) 50%
(c) 75%
(d) 99%
(d) 99%
An increase in overall gain will result in all of the following except:
(a) increase in image brightness throughout the display
(b) increase in output power
(c) increase in the amplification of returning signals
(d) decrease in the risk of bioeffects
(b) increase in output power
To increase the strength (amplitude) of weak amplitude echoes, the sonographer should increase:
(a) frequency
(b) PRF
(c) transmit gain
(d) gain
(d) gain
Reject eliminates:
(a) high amplitude signals
(b) low amplitude signals
(c) gray scale
(d) ring down
(b) low amplitude signals
The units for power are:
(a) W
(b) mW/cm squared
(c) dB
(d) Hz
(a) W
The units for wavelength are:
(a) mm
(b) cm squared
(c) dB
(d) Hz
(a) mm
The units for speed of sound are:
(a) m
(b) mm
(c) m/s
(d) Hz
(c) m/s
There have been no proven biological effects for unfocused transducer for intensities below:
(a) 1 W/cm squared
(b) 100 mW/cm squared
(c) 100 mW/cm squared SPTA
(d) 1,000 mW/cm squared SPTA
(c) 100 mW/cm squared SPTA
60 mm equals (blank) cm.
(a) 0.6 cm
(b) 6 cm
(c) 60 cm
(d) 600 cm
(b) 6 cm