UT Definitions and differences

Question 1

1)

What is Acoustic Impedance?

A) Concentration or convergence of energy into a smaller beam

B)The loss in Acoustic energy which occurs between any two points of travel

c) The product of the material density and the acoustic wave velocity within the materials

D) *The physical boundary between two surfaces

Answer 1

C) The product of the material density and the acoustic wave velocity within the materials

Question 2

2)

What is another definition for a Longitudinal Wave?

A) Shear Wave

B) Compressional wave

C) Rayleigh Wave

D) Surface Wave

Answer 2

B) Compressional Wave

Question 3

3)

What methods are used to display Ultrasonic wave imformation?

A) A-Scan, B-Scan, C-Scan
B) B-Scan, D-Scan, C-Scan
C)* A-Scan, D-Scan, F-Scan*

Answer 3

A) A-Scan, B-Scan, C-Scan

Question 4

4)

Match the definitions to the appropriate names
(Write down)

1) Concentration or convergence of energy into a smaller beam.
2) Where intervals of high and low acoustic transmission intensity cease to occur
3) The divergence of the sound beam as it travels through a medium
4) Fresnel Field: A field composed of complex and changing wave front characteristics

A) Near Field
B) Far Field
C) Focusing
D) Beam Spread

Answer 4

1,C.
2,B.
3,D.
4,A.

Question 5

5)

What are Ghost signals?

A) A signal caused by the PRF (Pulse Repetition Frequency) being set too high.
B) A Non-relevant indication
C) Also Referred to as ‘Grass’
D)* A + B*
E)* B + C*

Answer 5

D) A + B

Question 6

6)

Whats is Diffraction?

A) *Diffraction is where a materials characteristics cause the acoustic energy of a wave to change direction as it passes from an interface into the new material.

*B) Diffraction is the deflection of a wave front when passing the edge of a wave front.

C) *None of the above**

Answer 6

B) Diffraction is the delfection of a wave front when passing the edge of a wavefront.

Question 7

7)

What is Rarefaction?

A) The rate at which the individual pulses of acoustic energy are generated

B) The Characteristic of a material to change the direction of acoustic energy as it passes through an interface into the refracting material

C) The characteristic of a surface to change the direction of propagating acoustic energy; the return of sound waves from surfaces

D)The thinning out, or moving apart, of the consistent particles in the propagating medium due to the relaxation phase of an ultrasonic cycle.

Answer 7

D) The thinning out, or moving apart, of the consistent particles in the propagating medium due to the relaxation phase of an ultrasonic cycle

Question 8

8)

Whats the difference between the three terms; Velocity and Frequency?

A) Frequency is concerned with the speed by which sound waves travel through a medium, while Velocity is concerned with the number of cycles per given unit (e.g 1 second).

B) Velocity is concerned with the speed by which sound waves travel through a medium, while Frequency is concerned with the number of cycles per given unit (e.g 1 second).

Answer 8

B) Velocity is concerned with the speed by which sound waves travel through a medium, while Frequency is concerned with the number of cycles per given unit (e.g 1 second).

Question 9

9)

Whats the difference between Hash/Grass and Material noise?

A) Hash/Grass are extraneous signals caused by the structure of the material, whereas Material noise is caused by small inhomogeneties in the material or background.

B) Hash/Grass are numerous indications on the screen that indicate small inhomogeneties in the material or background, whereas material noise are extraneous signals caused by the structure of the material being tested.

C) None of the above

Answer 9

B) Hash/Grass are numerous indications on the screen that indicate small inhomogeneties in the material or background, whereas material noise are extraneous signals caused by the structure of the material being tested.*

Question 10

10)

What is a mode?

A) The display type; A-Scan, B-Scan, C-Scan
B) The manner in which acoustic energy is propagated through a material as characterised by the particle motion of the wave.
C) Where the surface changes the mode of propagation of acoustic energy from one mode to another.
D) The type of ultrasonic test: Immersion or contact

Answer 10

B) The manner in which acoustic energy is propagated through a material as characterised by the particle motion of the wave.