Quiz On Physics GK Question And Answers
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Physics is the branch of science. Take this quiz and learn more about the nature and properties of matter and energy.
- 1.The frequency closest to the lower limit of US is
- A.
19,000 kHz
- B.
10,000 MHz
- C.
20,000 msec
- D.
15,000 Hz
- 2.Put in decreasing order
- A.
Deca, deci, centi, micro
- B.
Deci, deca, centi, micro
- C.
Micro, centi, deca, deci
- D.
Centi, micro, deci, deca
- 3.Which of the following is determined by the source and the medium?
- A.
Frequency
- B.
Period
- C.
Propagation speed
- D.
Range resolution
- 4.As a result of _____________ the propagation sped increases
- A.
Increasing stiffness and increasing density
- B.
Increasing stiffness and increasing elasticity
- C.
Decreasing compressibility and decreasing density
- D.
Decreasing stiffness and decreasing density
- 5.Put in decreasing order of propagation speed.
- A.
Gas, liquid and solid
- B.
Solid liquid and gas
- C.
Liquid gas solid
- 6.If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happends to the wavelength?
- A.
Doubles
- B.
Halved
- C.
Remain the same
- D.
4 times greater
- 7.If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happend to the power?
- A.
Quadrupled
- B.
Doubled
- C.
Halved
- D.
Unchanged
- 8.What is the minimum value of the duty factor?
- A.
10.0
- B.
1%
- C.
1.0
- D.
0.0%
- 9.If a 5MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength?
- A.
Fat
- B.
Air
- C.
Muscle
- D.
Bone
- 10.As the impedances (z (rayls) = density (kg/m^3) x prop. speed (m/s) or acoustic resistance to sound traveling in a medium, becomes vastly different, the
- A.
Reflection increases
- B.
Transmission increases
- C.
Refraction increases
- D.
Absorption increases
- 11.With normal incidence, what factors affect refraction of US?
- A.
Propagation speeds
- B.
Frequencies
- C.
Attenuation coefficients
- D.
None of the above
- 12.The most likely amount of reflection at a boundary between soft tissue is:
- A.
1%
- B.
22%
- C.
34%
- D.
99%
- 13.How many cm are 60 millimeters
- A.
600
- B.
6
- C.
0.6
- D.
0.006
- 14.How is range ambiguity artifact eliminated?
- A.
Lower the PRF
- B.
Raise the PRF
- C.
Increase the gain
- D.
Use a lower frequency transducer
- 15.Under which of the following conditions is lateral resolution improved?
- A.
Decreased beam diameter
- B.
Decreased pulse duration
- C.
Decreased imaging depth
- D.
Decreased pixel size
- E.
Decreased spatial pulse length
- 16.Which transducer would be best to image superficial structures?
- A.
Small diameter, high frequency
- B.
Small diameter, low frequency
- C.
Large diameter, high frequency
- D.
Large diameter, low frequency
- 17.If the frame rate increases and the lines per frame is unchanged, what else must happen?
- A.
US speed increases
- B.
Frequency increases
- C.
Depth increases
- D.
Depth decreases
- 18.TRUE OR FALSEA system which was working well now does not display clear images in the far field. This may be a problem with the monitor.
- A.
True
- B.
False
- 19.If the output of an US machine is calibrated in dB and the output is increased by 20 dB, the beam intensity is increased
- A.
100 times
- B.
1,000,000 times
- C.
20 times
- D.
10 times
- 20.Which of the following will result in the greatest number of shades of grapy in a digital image display?
- A.
Large pixels with many bits/pixel
- B.
Small pixels with few bits/pixel
- C.
Many TV lines per frame
- D.
High contrast
- E.
Narrow dynamic range
- 21.With good images on the CRT but not on the strip chart recorder, one should
- A.
Increase the gain
- B.
Check the scan head
- C.
Check the same converter
- D.
Adjust the recorder
- 22.Compression is used to
- A.
Decrease the amplitude
- B.
Decrease the range of amplitudes
- C.
Decrease the range of frequencies
- 23.In which of these biologic tissues will sound waves propagate most quickly?
- A.
Tendon
- B.
Blood
- C.
Lung
- D.
Fat
- E.
Amniotic fluid
- 24.All of the following statements regarding in-vitro bioeffects are true EXCEPT?
- A.
In vitro bioeffects conclusions are clinically relevant
- B.
In vitro bioeffects are always real
- C.
In vitro bioeffects are vey important
- D.
In vitro bioeffects may not be applicable to clinical settings
- 25.Which of the following improves signal to noise ratio
- A.
Dynamic range
- B.
Frame averaging
- C.
Gray scale
- D.
Edge enhancement
- E.
Receiver gain
- 26.Under which circumstances is cavitation most likely to occur
- A.
High frequency and low power
- B.
High intensity and high frequency
- C.
Low intensity and low frequency
- D.
Low frequency and high signal amplitude
- 27.What is displayed on the y-axis of an m-mode image?
- A.
Time
- B.
Time of flight
- C.
Echo intensity
- D.
Red blood cell velocity
- 28.An amplifier of an ultrasound system increases the voltage of a signal from 0.0001 to 0.1 volt. What is the amplification
- A.
60 dB
- B.
30 dB
- C.
1,000 dB
- D.
90 dB
- 29.The impedances of tissue is 3 x 10^5 rayls and for the PZT crystal is 6 x 10^6 rayls. What is the best impedance for the matching layer?
- A.
36 x 10^5
- B.
3,600
- C.
10,000
- D.
9.5 x 10 ^5
- E.
9 x 10^4
- 30.Put in increasing order of propagation speed
- A.
Air bone water
- B.
Bone water air
- C.
Air water bone
- D.
Water air bone
- E.
Bone air water
- 31.What is propagation speed determined by
- A.
Wavelength
- B.
Intensity and density
- C.
Amplitude
- D.
Density and elasticity
- E.
Density and amplitude
- 32.If 300,000 cycles occur in a second, what is the wave's frequency?
- A.
3 MHz
- B.
30 kHz
- C.
300 MHz
- D.
3 kHz
- E.
0.3 MHz
- 33.All of the following will improve temporal resolution EXCEPT
- A.
Increased line density
- B.
Single rather than multi focus
- C.
Higher frame rate
- D.
Shallower depth of view
- E.
Slower speed of sound in a medium
- 34.What component of a transducer changes electrical to mechanical and mechanical back to electrical engergy?
- A.
PZT
- B.
Transducer
- 35.What are typical clinical Doppler frequencies
- A.
1 - 10,000 Hz
- B.
1 - 10 MHz
- C.
2 - 1,000 kHz
- D.
40 - 45 kHz
- 36.What is the actual time that an US machine is creating a pulse?
- A.
Duty factor
- B.
Period
- C.
Pulse period
- D.
Pulse duration
- 37.What is the significance of gray scale variation in the spectrum of a pulssed wave Doppler display?
- A.
It represents the number of red blood cells creating the reflection
- B.
It represents the velocity of red blood cells
- C.
It represents the speed of red blood cells
- D.
It represents the convergence of red blood cell lamina
- E.
It determines the enseble length
- 38.What is the production of deformation from voltage called?
- A.
Piezoelectricity
- B.
Impedance
- C.
Cogeneration
- D.
Flux
- 39.What is the elimination of voltages that do not exceed a certain level?
- A.
Amplification
- B.
Decompensation
- C.
Reject
- D.
Demodulation
- 40.How many data bits are needed to represent 46 gray shades?
- A.
46
- B.
5
- C.
6
- D.
8
- 41.Which of the following is associated with cavitation?
- A.
Thermal index
- B.
Snell's Law
- C.
Avagadro's Number
- D.
Mechanical index
- 42.All of the following are true of normal cavitation EXCEPT:
- A.
Harmful bioeffects are commonly observed
- B.
It is also known as inertial cavitation
- C.
Only a 10% increase in pressure is needed to convert to this from stable cavitation
- D.
Temperatures in the thousands of degreesare created
- E.
It is consistent with shock waves
- 43.The packet size in color Doppler refers to the number of :
- A.
Pulses per second
- B.
Sample volumes per scan line
- C.
Scan lines per unit area
- D.
Pulse - listen cycles per acoustic scan line
- E.
Pulses required to create one frame
- 44.A commonly used process for determining direction in a Doppler instrument is
- A.
Zero crossing detection
- B.
Autocorrelation
- C.
Phase quadrature detection
- D.
Range gating
- E.
Spectral analysis
- 45.What is the maximum velocity limit for a 3 MHz CW Doppler unit operating at a depth of 4cm?
- A.
40 cm/s
- B.
200 cm/s
- C.
2.5 m/s
- D.
4 m/s
- E.
None of the above
- 46.What method is used to steer the color beam with a linear array transducer?
- A.
Mechanical
- B.
Electronic time delays
- C.
Electronic voltage variation
- D.
Apodization
- E.
The color beam cannot be steered with a linear array transducer
- 47.Increasing the wall filter during Doppler sampling will:
- A.
Increase visibility of low velocity signals
- B.
Increase spectral broadening
- C.
Decrease bandwidth
- D.
Reduce display of low frequency shifts
- E.
Reduce aliasing
- 48.What would be the most likely result from increasing the transmit frequecy of the color Doppler?
- A.
Improve sensitivity to slow flow
- B.
Improved penetration for imaging flow in deep tissues
- C.
Reduced flash artifact obscuring small vessel flow
- D.
Reduced color Doppler aliasing
- E.
Improve visibility of complex flow hemodynamics
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