SPI Practice Test Questions And Answers!

2.

_____ is the distance covered by one cycle.

Pulse length
Wavelength
Cycle distance
Cycle duration

Correct Answer

A. Wavelength

Explanation

wavelength is the length of space that one wave occupies, usually measured in mm, meters, inches.

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10

3.

______ is the time to complete one cycle.

Pulse duration
Pulse period
Period
Duration period

Correct Answer

A. Period

Explanation

The correct term for the time it takes to complete one cycle in a periodic wave or oscillation is "period." The period (denoted by the symbol 'T') is the reciprocal of the frequency (f) of the wave and can be calculated using the following formula:T = 1/fThe period is usually measured in seconds (s) or milliseconds (ms) and represents the time interval between two consecutive points in the same phase of the wave, such as two consecutive peaks or troughs. Understanding the period of a wave, along with other related concepts like frequency, wavelength, and amplitude, is essential in the study of oscillatory phenomena, including sound waves, electromagnetic waves, and simple harmonic motion.

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4.

Which is not an acoustic variable?

Density
Pressure
Distance
Intensity

Correct Answer

A. Intensity

Explanation

Intensity is a crucial acoustic variable that quantifies the energy carried by a sound wave per unit area. It is an essential factor in determining the perceived loudness of a sound, as a higher-intensity sound wave produces a louder sound. The unit of measurement for sound intensity is watts per square meter (W/m²). The intensity of a sound wave decreases with increasing distance from the source due to the spreading of the wave in space. This phenomenon is known as the inverse square law, which states that the intensity of a sound wave is inversely proportional to the square of the distance from the source.

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7

5.

Propagation speed = _______ x wavelength

Pulse duration
Period
Number of cycles in the pulse
Frequency

Correct Answer

A. Frequency

Explanation

The propagation speed of a wave is equal to the frequency of the wave multiplied by its wavelength. This relationship is defined by the wave equation, where the speed of a wave is determined by the frequency at which it oscillates and the distance it travels per cycle (wavelength). Therefore, the correct answer is frequency.

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14

6.

All of the following are true EXCEPT:

Two waves with identical frequencies must interfere constructively.
Constructive interference is associated with waves that are in-phase.
Out-of-phase waves interfere destructively.
Waves of different frequencies may exhibit both constructive and destructive interference at different times.

Correct Answer

A. Two waves with identical frequencies must interfere constructively.

Explanation

This statement is not true because waves with identical frequencies can interfere constructively or destructively depending on their phase. If the waves are in-phase, they will interfere constructively, but if they are out-of-phase, they will interfere destructively.

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12

7.

The effects of soft tissue on the ultrasound are called:

Acoustic proliferation properties
Dynamic effects
Acoustic propagation properties
Biologic effects

Correct Answer

A. Acoustic propagation properties

Explanation

Soft tissue has certain properties that affect the propagation of ultrasound waves. These properties are referred to as acoustic propagation properties. This includes the ability of soft tissue to transmit, absorb, and scatter ultrasound waves. Understanding these properties is important in medical imaging as it helps in interpreting ultrasound images and diagnosing various conditions.

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8

8.

The frequency closest to the lower limit of the ultrasound is:

19.000 kHz
10.000 MHz
22.000 msec
20,000 Hz

Correct Answer

A. 20,000 Hz

Explanation

The frequency closest to the lower limit of ultrasound is 20,000 Hz (or 20 kHz). Ultrasound refers to sound waves with frequencies higher than the upper limit of human hearing, which is approximately 20,000 Hz. The lower limit of ultrasound is typically considered to be around 20 kHz, while the upper limit can extend to several gigahertz (GHz) for some applications. Ultrasound waves with frequencies close to the lower limit, such as 20 kHz, are often used in various applications, including medical imaging, sonar, and non-destructive testing. At these frequencies, ultrasound can effectively propagate through various mediums, such as water, tissue, and metals, and provide valuable information for diagnosis, detection, or material characterization.

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6

9.

Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?

30 kHz
8 MHz
8.00 Hz
3.00 kHz
15 Hz

Correct Answer

A. 30 kHz

Explanation

Ultrasonic waves refer to sound waves that have a frequency above the range of human hearing, which typically starts at around 20 kHz. Therefore, the sound wave with a frequency of 30 kHz is considered ultrasonic. Diagnostic imaging, such as ultrasound imaging, utilizes sound waves in the megahertz range (MHz), typically between 2-18 MHz, to create detailed images of internal body structures. Since 30 kHz is below this range, it is least useful in diagnostic imaging.

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5

10.

The speed of the ultrasound in soft tissue is closest to:

2 km/sec
4 km/msec
1540 m/s
500 mm/sec

Correct Answer

A. 1540 m/s

Explanation

The speed of ultrasound in soft tissue is closest to 1,540 m/s (or 1.54 km/s). Ultrasound waves are high-frequency sound waves that have a higher frequency than the audible range for humans. In soft tissues, such as muscle, fat, and blood, the speed of ultrasound is relatively constant and is typically between 1,540 m/s and 1,580 m/s. This property allows ultrasound waves to be used in medical imaging, such as sonography, where the reflections of ultrasound waves are used to produce images of internal organs and tissues. Ultrasound is also used in other applications, such as non-destructive testing and underwater sonar, due to its ability to propagate through various mediums and provide detailed information about the materials it interacts with.

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24

11.

What is the frequency of a wave with a 1 msec period?

10.00 Hz
1.00 kHz
1 kHz
1 MHz

Correct Answer

A. 1 kHz

Explanation

The frequency of a wave is the number of complete cycles of the wave that occur in one second. In this case, the wave has a period of 1 millisecond, which means it completes one cycle in 1 millisecond. To find the frequency, we can use the formula: frequency = 1 / period. Therefore, the frequency of the wave with a 1 msec period is 1 kHz (1 kilohertz), which means it completes 1,000 cycles in one second.

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6

12.

As a result of _____ the propagation speed increases.

Increasing stiffness and increasing density
Increasing stiffness and increasing elasticity
Decreasing compressibility and decreasing density
Decreasing stiffness and decreasing density

Correct Answer

A. Decreasing compressibility and decreasing density

Explanation

When the compressibility and density of a material decrease, the propagation speed increases. This is because when a material is less compressible, it is able to transmit waves more efficiently, resulting in a faster propagation speed. Similarly, when the density of a material decreases, there are fewer particles to interact with, allowing the waves to travel faster. Therefore, decreasing compressibility and density both contribute to an increase in propagation speed.

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5

13.

Which of the following is determined by the source and the medium?

Frequency
Period
Propagation speed
Range resolution

Correct Answer

A. Range resolution

Explanation

Range resolution is determined by the source and the medium. Range resolution refers to the ability of a system to distinguish between two closely spaced targets in the range direction. The source characteristics, such as the wavelength of the signal, and the properties of the medium through which the signal propagates, such as the speed of propagation, affect the range resolution. By controlling these factors, the source and the medium can influence the ability of the system to resolve targets at different ranges.

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20

SPI Practice Test Questions And Answers!

Sound waves are:

Quiz Preview

_____ is the distance covered by one cycle.

______ is the time to complete one cycle.

Which is not an acoustic variable?

Propagation speed = _______ x wavelength

All of the following are true EXCEPT:

The effects of soft tissue on the ultrasound are called:

The frequency closest to the lower limit of the ultrasound is:

Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?

The speed of the ultrasound in soft tissue is closest to:

What is the frequency of a wave with a 1 msec period?

As a result of _____ the propagation speed increases.

Which of the following is determined by the source and the medium?