B a leak that is so small as to be virtually

b.
A leak that is so small as to be virtually impossible to detect.
c.
A leak from an isolated pocket within a vacuum system.
d.
Out gassing vapors within a vacuum system.
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55.In AET the location of the defect is done by :
56.Placing the snifter probe or gun of a halogen diode leak detector in a stream of
pure refrigerant.
57.Acoustic emission testing can be used :
58.Small leaks can be tested by which of the following methods.
a.
Liquid penetrant testing & halogen leak testing.
b.
Ultrasonic testing and acoustic emission testing.
c.
Helium leak testing and acoustic emission testing.
d.
Helium leak testing and liquid penetrant testing.
59.Using infrared detectors it is possible :
60.Which one of the following is the major disadvantage of thermography testing :
61.The sensor used in thermography testing equipment for detecting infrared
waves is :
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62.The total radiant power emitted by a black body can be obtained from :
a.
Planck’s law.
b.
Stefan boatzman relation.
c.
Wein’s law.
d.
None of the above.
63.The wavelength of infrared radiation from a body can be determined.
64.Infrared measurements for NDT are normally carried out in the wavelength
region.
65.The main absorbing molecules in the atmosphere, which attenuates IR
maximum.
66.The main advantage theromgraphy over other contact temperature
measurements methods is :
a.
It is fast and safe.
b.
It is non contact and presents an instantaneous view of the entire field
covered.
c.
It can be used for HV voltage lines.