Q/a Flashcards
Which of the following circuits provides short duration, high energy pulses which are used to excite the transducer?
(a) The pulse generator
(b) The amplifier
(c) The transducer
(d) The clock
A. the pulse generator
Which of the following circuits provide current to OPERATE the ultrasonic instrument?
(a) The pulse generator
(b) The amplifier
(c) The power supply
(d) The sweep generator
C. Power supply
The longitudinal wave incident angle at which the refracted shear wave angle equals ninety degrees is called:
(a) The Snell angle
(b) The Snell constant
(c) The first critical angle
(d) The second critical angle
D. Second critical angle
In immersion testing, the position of the search unit is often varied to transmit sound into the test part at various angles to the front surface. Such a procedure is referred to as:
(a) Angulation
(b) Dispersion
(c) Reflection testing
(d) Refraction
A. Angulation
The angle of a refracted shear wave generated as a sound wave passes at an angle through an acoustic interface is dependant on:
(a) The acoustic impedances of the materials of each side of the interface
(b) The frequency of the incident sound wave
(c) The wavelength of the incident sound wave
(d) The hardness of the materials on each side of the interface
A. The acoustic impedances of the materials of each side of the interface
An ultrasonic instrument control which allows moving an A scan display to the LEFT or RIGHT WITHOUT CHANGING THE DISTANCE between any echoes displayed is called:
(a) The sweep length or range control
(b) The damping control
(c) The sweep delay
(d) The pulse length control
C. Sweep delay
A more highly damped transducer crystal results in:
(a) Better resolution
(b) Better sensitivity
(c) Lower sensitivity
(d) Poorer resolution
A. Better resolution
Scattering of an ultrasonic beam is most pronounced when:
(a) Material grain size and wavelength are comparable
(b) Low frequency transducers are used
(c) Large wavelengths are used for ultrasonic testing
(d) None of the above
A. Material grain size and wavelength are comparable
Which technique would most likely be used to examine a weld, with the weld cap still in place?
(a) Through transmission testing
(b) Angle beam testing
(c) Straight beam testing
(d) None of the above
B. Angle beam testing
The maximum frequency usually used for contact testing is: (a) 1 MHz
(b) 5 MHz
(c) 10 MHz
(d) 25 MHz
B. 5MHz
Typical ultrasonic testing frequencies are:
(a) 50 kHz to 1 MHz
(b) 200 kHz to 25 MHz
(c) 10 MHz to 100 MHz
(d) 1MHzto5MHz
D. 1MHz to 5MHz
A disadvantage of using a high frequency ultrasonic transducer is:
(a) It provides a smaller beam angle and better resolving power
(b) It provides a larger beam angle and poorer resolving power
(c) It is scattered more by coarse grained material
(d) It is scattered less by coarse grained material
C. It is scattered more by coarse grained material
Which of the following circuits provides timing signals to the pulser?
(a) The clock
(b) The amplifier
(c) The pulse generator
(d) The sweep generator
A. The clock
With longitudinal wave incident at angles between the first and second critical angles:
(a) The sound beam is totally reflected
(b) Only shear waves are produced in the second material
(c) Shear waves and longitudinal waves are produced in the second material
(d) Only longitudinal waves are produced in the second material
Only shear waves are produced in the second material
An ultrasonic wave in which particle displacement is 90 degrees to the direction of wave propagation is called a:
(a) Longitudinal wave
(b) Shear wave
(c) Compressional wave
(d) Plate wave
B. Shear wave
An ultrasonic instrument control which is used to expand or contract the horizontal base line of an A scan display is called:
(a) The sweep length or range control
(b) The damping control
(c) The sweep delay
(d) The pulse length control
A. The sweep length or range control
The speed of sound in a given material depends on:
(a) The specific acoustic impedance of the material
(b) The acoustic impedance and density of the material
(c) The density and elasticity of the material
(d) The piezo-electric resistance of the material
C. The density and elasticity of the material
The first critical angle is defined as the longitudinal wave incident angle which results in:
(a) A refracted longitudinal wave of ninety degrees
(b) A refracted shear wave of ninety degrees
(c) Complete reflection of the shear wave
(d) None of the above
A. A refracted longitudinal wave of ninety degrees
The portion of a test piece which is represented by the CRT screen area from zero to the rightmost edge of the initial pulse is called:
(a) The dead zone
(b) The near field
(c) The near zone
(d) The far zone
B. The near field
Spurious indications might be caused by which of the following?
(a) Mode conversion from beam spread in a long specimen
(b) Surface waves generated during straight beam testing
(c) A test piece with a smooth machined surface
(d) All of the above
A. Mode conversion from beam spread in a long specimen
An ultrasonic test using a straight beam contact search unit is being conducted through the thickness of a flat part such as a plate. This test should detect:
(a) Laminar-type flaws with major dimensions parallel to the rolled surface
(b) Transverse-type flaws with major dimensions at right angles to the rolled surface
(c) Radial flaws with major dimensions along length but radially oriented to the rolled surface
(d) None of the above
A. Laminar-type flaws with major dimensions parallel to the rolled surface
Transducer focal lengths are normally specified as:
(a) Distance in steel
(b) Distance in aluminium
(c) Distance in air
(d) Distance in water
A. Distance in steel
Spurious or nonrelevant indications might be suspected if:
(a) Indications are unusually consistent in amplitude and appearance
(b) There are strong indications in localised areas
(c) The indications are localised and repeatable
(d) None of the above
(a) Indications are unusually consistent in amplitude and appearance
A disadvantage of lithium sulfate as a transducer material is that:
(a) It is an inefficient receiver of ultrasonic energy
(b) It is soluble in water
(c) It is not piezo- electric
(d) It has extremely coarse grain structure
B. It is soluble in water