Leak Testing Review Questions

16 Dec.,2024

 

Leak Testing Review Questions

Leak Testing Review Questions

  1. Which of the following systems or components are not good candidates for leak testing? a. Piping and pressure vessels. b. Refrigeration piping. c. Vacuum chambers. d. Sintered material components.

    With competitive price and timely delivery, TNMA sincerely hope to be your supplier and partner.

  2. A helium mass spectrometer is used in which of the following NDT techniques or methods? a. Leak testing. b. X-ray spectroscopy. c. Optical holography. d. Acoustic holography.

  3. Which of the following is a technique of leak testing? a. Static. b. Gaseous diffusion. c. Dynamic. d. Detector probe.

  4. Potentially, the most sensitive leak testing technique is the: a. bubble test. b. pressure change test. c. mass spectrometer test. d. liquid penetrant test.

  5. Establishing differential pressure between the test object and environment is an essential element in which of the following NDT methods? a. X-ray diffraction. b. Leak testing. c. Neutron radiography. d. Electromagnetic testing.

  6. Which of the following best describes the type of leak test used when the interior of the test object is evacuated and a tracer gas is applied to the exterior, while the leak detector is connected to the evacuating system? a. Static leak test. b. Helium leak test. c. Dynamic leak test. d. Halogen leak test.

  7. Assuming no significant leakage, if the temperature increases, during a pressure drop leak test, the pressure in the system under test would: a. increase. b. remain the same. c. decrease. d. first increase, then decrease to its former level.

  8. If the sensitivity of the halogen leak detector is constant throughout a test, which of the following is true upon completion of the test? a. No leaks smaller than a certain size have gone undetected. b. The total leak rate of the test object is less than a certain amount. c. The instrument and the test procedure were capable of detecting leakage of a certain size during the test. d. The instrument and test procedure were only capable of detecting leakage of a certain size upstream of the tracer gas during the test.

    Want more information on Gas Meter Water Leakage Test Bench? Feel free to contact us.

  9. All leak detection techniques are dependent upon: a. barometric pressure. b. gas or fluid flow. c. mass spectrometer analysis. d. mean free paths of helium flow.

  10. In an evacuated system, sensitivity of a pressure change leak test is dependent not only on the pressure change observed, but also on the degree of outgassing. Outgassing is best defined as: a. the release of gas from materials in a vacuum. b. being directly proportional to the temperature of the gas. c. the viscosity of the pressurizing gas. d. the drop in test pressure due to leakage from the vacuum manifold.

  11. In leak testing by pressure drop method, the leak rate is given by the formula: if volume of the vessel (V) is 10 liters, drop of pressure (P) is 0. Kg/cm and time take (T) for this pressure drop is two hours. Leak rate is: a- 30 cc/sec b- 1 cc/sec c-0 cc/sec d- 5 x 10-4 cc/sec

  12. After hydro test (to check the integrity of the vessel), bubble test using soap solution, has to be carried out. Which of the following precautions are necessary to get reliable results: a- Vessel must be thoroughly dried before leak testing. b- The job must be cleaned to remove grease, oil dirt, dust etc. c- Pressure gauge must be properly calibrated and should have a suitable range d- All above precautions are necessary

C. detrimental to environment 20 - helium mass spectrometer used for a- in vacuum b- leak and leakage location 21 - which gas is used as tracers gas, which is also inert. A. Helium B. nitrogen C. oxygen 22 - why hydrogen not used as tracer gas? A- nitrogen purge equipment before B- nitrogen + hydrogen dangerous (considered very dangerous) 23. Leaks can be tested by A. bubble leak testing B. radiographic testing C. acoustic emission testing D. helium leak testing E. both A and D 24. The SI unit of pressure is: A. Pa B. torr C. mm of Hg D. psi 25 - Which of the following term is used to indicate the difference between absolute pressure and atmospheric pressure? A. Ambient pressure B. Negative pressure C. Air pressure D. Gage pressure 26 - A virtual leak is: A. a leak that is small enough to be within the acceptance standards. 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 of the testing object. 27 - In mass spectrometer pumping speed and conductance are A. directly proportional B. different terms for the same function C. different functions with the same unit of measurement

D. reciprocal to each other. 28 - What are three essential parameters involved in the dynamics of gases? A. Volume, temperature, pressure B. Density, atomic weight, pressure C. Pressure, specific gravity, atomic weight D. Volume, temperature, density 29 - When performing a mass spectrometer leak detection test of an ultra high vacuum system: A. a preliminary hydrostatic test should be performed B. a preliminary hydrostatic test should not be performed C. a pressure test should be employed in preference to a vacuum test D. none of the above 30. The pressure of a gas relative to a vacuum and independent of atmosphere pressure is A. partial pressure B. gauge pressure C. absolute pressure D. vapor pressure 31. Total atmospheric pressure at sea level is 100 kPa. Find the partial pressure of helium (He), if helium concentrations is 4 ppm (by volume). A. 0 kPa B. 0 kPa C. 0% D. 4 Pa 32 - The passage of a gas by diffusion through a solid material where there is no physical leak in the sense of an opening or defect, is called: A. permeation B. adsorption C. absorption D. capillary action 33. In the molecular mode, helium will flow through a leak: A. at the same rate as air B. at a faster rate than air C. at a slower rate than air D. in a turbulent flow pattern 34. In lieu of air, which one of the following gases would be the best choice as the pressurizing medium for a pressure change measurement test? A. Nitrogen

A. Reservoir type leak B. Non reservoir type leak C. Porous plug D. Capillary standard 42. The physical hole is represented by the word A. leak B. leakage C. leakage rate D. any of the above 43. Leak testing is used A. to prevent material loss B. to prevent contamination and hazard C. to distinguish between reliable and non reliable components D. all of the above 44. Increasing the detector probe speed over the area being examined will result in A. an increase in test sensitivity B. a decrease in test sensitivity C. a decrease in response time D. a decrease in instrument sensitivity 45. A sensor that can be used to measure dry bulb temperature in pressure change measurement test systems which consist of a bimetallic junction that produces an electromotive force (emf) that varies with temperature is known as a: A. resistance bridge B. ionization of molecules C. vacuum pump system speed D. thermocouple 46. As the elevation above sea level increases, the barometric pressure: A. remains the same B. decrease C. increases D. none of the above 47. What parameter can directly affect the sensitivity of any vacuum box bubble test? A. Slight residual magnetism in test specimen. B. Amount of pressure differential created with the box. C. Ambient air dew point temperature is more that 25 ºF. D. all of the above

For more information, please visit Gravimetric & Piston Method Water Meter Test Bench.

  1. Which is the basic type of true defect that would be indicated during a bubble leak test by a continuous flow of bubbles? A. Lack of fusion at root of weld B. A hole or crack through the test boundary C. Slab inclusion in center of weld D. Extended area of surface defects or cracks
  2. The term used to indicate pressure above the zero value corresponding to a perfect vacuum is A. gauge pressure B. absolute pressure C. air pressure D. water pressure
  3. The general gas law showing the relationship of pressure, temperature and volume of an ideal gas is expressed by which one of the following relationships? A. PT/V = Constant or P1 T1 = P2 T2 (when V1 = V2) B. TV/V = nR or T1 V1 = T2 V2 (when P1 = P2) C. PV = nRT or P1 T2 = P2 T1 (when V1 = V2) D. PV=nR or P1 V1 =P2V1 (when T1 = T2) 51 - The spontaneous evolution of gas and vapor from materials in a vacuum as pressure is reduced is called: A. outgassing B. hydrofoiling C. gasification D. reticulation
  4. Which of the following gases is most practical as the pressurizing medium for a pressure change measurement test? A. Argon B. Hydrogen C. Air D. All of the above 53 - Most sensitive method of leak testing? Helium mass spectrometer