NDT Exam Questions with 100 Verified

NDT Exam Questions with 100% Verified Correct Answers Tomography allows me to

• Obtain a color image
• Discretize the information of the investigated space
• Produce a map of reflected events - Correct Answer - Discretize the information of the investigated

space In a seismic refraction survey, the geophone placed at a distance of 3p (p = depth of the first layer) from the source will record which waves first?

• Direct waves
• Refracted waves
• Reflected waves - Correct Answer - Refracted waves

In which of the following media does the velocity of P-waves propagate the fastest?

• Bricks
• Wood
• Concrete - Correct Answer - Concrete

What does the investigable depth with surface waves depend on?

• Phase velocity
• Wavelength
• Signal generation time - Correct Answer - Wavelength

In which material does a GPR survey with a 500MHz antenna provide the best resolution?

• Air
• Freshwater
• Saltwater - Correct Answer - Air

Indicate the correct order of decreasing velocity:

• P-waves - S-waves - R-waves 1 / 3

• R-waves - S-waves - P-waves
• S-waves - P-waves - R-waves - Correct Answer - P-waves - S-waves - R-waves

In reflection seismic surveys, geophones are positioned:

• Inside the ground roll area
• On the perimeter of the ground roll area
• Outside the ground roll area - Correct Answer - Outside the ground roll area

In a reflection seismic survey, which waves provide higher resolution?

• S-waves
• P-waves
• R-waves - Correct Answer - S-waves

Which GPR antenna allows for investigation at greater depths?

• 200MHz
• 50MHz
• 700MHz - Correct Answer - 50MHz

Which of the following statements is correct?

• P-waves are suitable for distinguishing between clay and saturated sand
• S-waves are suitable for distinguishing between dry and wet sand
• P-waves are suitable for distinguishing between clay and dry sand - Correct Answer - P-waves are

suitable for distinguishing between clay and dry sand When conducting geoelectric measurements to investigate depth, what should I do?

• Increase the inter-electrode distance
• Maintain a constant distance between electrodes
• Bring the electrodes closer together - Correct Answer - Increase the inter-electrode distance

What is the temporal sampling frequency for a 200MHz GPR antenna?

• 200MHz 2 / 3

• 300MHz
• 800MHz - Correct Answer - 800MHz

To filter direct arrivals, I can:

• Place geophones in the ground roll area
• Place geophones for both P and S waves
• Place groups of geophones at each measurement point - Correct Answer - Place groups of

geophones at each measurement point

The geometric coefficient in geoelectric measurements defines:

• The position of the electrodes (or distance)
• The transmitted electrical energy
• The measured electrical energy - Correct Answer - The position of the electrodes (or distance)

How much should be the time delay between two signals to be distinguishable?

• Less than twice the period
• At least half the period
• At least four times the period - Correct Answer - At least half the period

In tomographic measurements:

• Absorption phenomena are smaller
• Spherical divergence is irrelevant
• Multiple sources can be used simultaneously - Correct Answer - Absorption phenomena are

smaller

The dromochrones of two conjugate shots in a seismic survey have:

• The same slope
• Different slopes
• Always the same length - Correct Answer - The same slope

What is the physical principle underlying the study of surface waves?

• Total reflection of a P-wave
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