Level 2 Flashcards
Mechanical wave motion requires
a) high pressure
b) low pressure
c) particle motion
d) ionic bonding and disbonding
C
In an homogenous and isotropic elastic medium such as low carbon steel, sound velocity a) decreases with distance from source b) varies with direction c) is constant in all directions d) depends on frequency
C
The amount of time between two compressions, or two rarefactions of an elastic wave is called a) wavelength b) period c) frequency d) velocity
B
The velocity of sound is
a) constant for all materials
b) varies with frequency
c) varies inversely with wavelength
d) is characteristic of a material
D
Compared to the atomic or molecular spacing of a material, ultrasonic wavelengths are
a) much greater
b) smaller
c) about the same distance 2
d) are multiples of the atomic spacing
A
The elastic wave that has particle motion parallel to the direction of wave propagation is called
a) longitudinal wave
b) compression wave
c) density wave
d) all of the above
D
In Rayleigh waves, particle motion is
a) parallel to the direction of wave propagation
b) right angles to the direction of wave propagation
c) retrograde
d) in counter clockwise ellipses
D
Rayleigh waves can be used in steel to penetrate up to
a) 10mm
b) 10cm
c) 1m
d) 1 wavelength
D
In bending waves (plate wave mode) particles in the middle zone of the plate vibrate
a) in longitudinal mode
b) in shear mode
c) in Rayeigh mode
d) not at all
B
In the Lamb wave called a dilational wave, particles in the middle zone of the plate vibrate
a) in longitudinal mode
b) in shear mode 3
c) in Rayleigh mode
d) not at all
A
If one sound beam passes through another moving in the opposite direction, the result will be,
a) a change in amplitude
b) a change in direction
c) a change in frequency
d) no change
A
In a standing wave, nodes and antinodes are separated by
a) 1/4 wavelength
b) 1/2 wavelength
c) 1 wavelength
d) 2 wavelengths
A
Standing waves are generated in ultrasonic testing for
a) through testing (pitch-catch)
b) resonance thickness testing
c) flaw detection
d) B-scans
B
Specific acoustic impedance is the product of
a) density and permittivity
b) hardness and velocity
c) velocity and density
d) specific activity and amplitude
C
Poisson’s ratio is expressed in units of
a) m/s
b) Pa
c) N/m24
d) no units, it is dimensionless
D
Frequency can be expressed in terms of
a) 1/s (s=seconds)
b) cps
c) Mhz
d) all of the above
D
The ratio of sound velocity in water to the longitudinal velocity of sound in steel is very nearly
a) 1:1
b) 1:2
c) 1:4
d) 1:5
C
Rayleigh wave velocities for a given material are always
a) greater than longitudinal wave velocities
b) greater than transverse wave velocities
c) less than transverse wave velocities
d) about the same as shear wave velocities
C
The ratio of the incident sound pressure to the reflected sound pressure is called the
a) acoustic impedance
b) acoustic intensity
c) coefficient of reflection
d) coefficient of transmission
C
The ratio of the incident sound pressure to the transmitted sound pressure is called the a) acoustic impedance b) acoustic intensity 5 c) coefficient of reflection d) coefficient of transmission
D
When is the coefficient of transmission a negative value?
a) if Z incident is less than Z transmitted
b) If Z incident is greater than Z transmitted
c) if Z incident equals Z transmitted
d) never
D
Incident sound pressure plus reflected sound pressure equals
a) 0
b) 1
c) transmitted sound pressure
d) none of the above
C
Total incident sound intensity can be calculated from
a) the sum of the reflected and transmitted intensities
b) the difference between reflected and transmitted intensities
c) R plus D (reflection and transmission coefficients)
d) R plus D (reflection and transmission coefficients)
A
(Sin a1) (C2) = (Sin a2) C1) is a form of
a) Krautkramer’s law
b) Snell’s law
c) Boyle’s law
d) Hooke’s law
B