1. Slower velocities may indicate ___________
a) Good quality and continuity of the material
b) Good quality and discontinuity of the material
c) Bad quality and continuity of the material
d) Concrete with many voids
Explanation: Slower velocities may indicate concrete with many cracks or voids, while higher velocities indicate good quality and continuity of the material.
2. Mechanical pulse having an oscillation frequency in range of `_____________
a) 30 kHz to 40 kHz
b) 40 kHz to 50 kHz
c) 50 kHz to 60 kHz
d) 60 kHz to 70 kHz
Explanation: Mechanical pulse having an oscillation frequency in range of 40000 Hz to 50000 Hz.
3. The number of cylces per second is the definition of ____________
a) Wave speed
b) Frequency
c) Hertz
d) Velocity
Explanation: One hertz (Hz) stands for one cycle per second and it is the SI unit of frequency. Velocity means displacement covered per second.
4. A discontinuity that occurs during the casting of molten metal which may be caused by the splashing, surging, interrupted pouring is ___________
a) Burst
b) Cold shut
c) Flaking
d) Blow hole
Explanation: A discontinuity that occurs during the casting of molten metal which may be caused by the splashing, surging, interrupted pouring, or the meeting of two streams of metal coming from different directions is called cold shut.
5. When the motion of the particles of a medium are at right angles to the direction of wave motion, the wave being transmitted is called a ___________
a) Longitudinal wave
b) Shear wave
c) Surface wave
d) Lamb wave
Explanation: When the motion of the particles of a medium are at right angles to the direction of wave motion, the wave being transmitted is called a longitudinal wave.
6. A second name for compression wave is __________
a) Longitudinal wave
b) Shear wave
c) Surface wave
d) Lamb wave
Explanation: Lamb waves are similar to longitudinal waves, with compression and rarefaction, but they are bounded by the sheet or plate surface causing a wave-guide effect.
7. The interference field near the face of a transducer is often referred to as the ______________
a) Fresnel zone
b) Acoustic impedance
c) Exponential field
d) Phasing zone
Explanation: Radio frequency line of sight is defined by Fresnel Zones which are ellipse shaped areas between any two radios.
8. The _________ compressive strength required from structural consideration.
a) Nominal
b) Minimum
c) Maximum
d) No
Explanation: Option d can be eliminated easily because we need atleast some compressive strength. The minimum compressive strength required from structural consideration.
9. The adequate workability necessary for _________ compaction with the compacting equipment available.
a) Half
b) Quarter
c) Full
d) Double
Explanation: Option d can be eliminated easily because double compaction is not possible. The adequate workability necessary for full compaction with the compacting equipment available.
10. __________ water-cement ratio content to give adequate durability for the particular site conditions.
a) Minimum
b) Nominal
c) .5
d) Maximum
Explanation: Maximum water-cement ratio and/or maximum cement content to give adequate durability for the particular site conditions. It helps to avoid shrinkage cracking due to temp cycle in mass concrete.