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- 1. KARPAGAM INSTITUTE OFTECHNOLOGY COIMBATORE - 105 DEPARTMENT OF MECHANICAL ENGINEERING Academic Year: 2020 - 2021 (ODD Semester) MCQ Test UNIT III Subject Code & Name : ME8097 –Non Destructive Testing and Evaluation PART A 1 ___________ testing technique allows the visualization of heat patterns on an object a) Thermography b) thermal imaging c) infrared thermography d)All of the above 2 The temperature differences observed on the investigated surface during inspection will be monitored by __________ camera a) An infrared b) Thermal c) Both a and b d) None of the above 3 Which of the following is not the characteristics of infrared ? a)It is sometime called as “heat ray” b) Its wavelength is larger than the visible light c) It’s a kind of electromagnetic wave d)It cannot travel through vacuum 4 _________ is the distance between successive crest of a wave , especially in an electromagnetic wave. a) Speed of light b) Frequency c) Wavelength d)None of the above 5 The relationship between wavelength and frequency for electromagnetic wave is a) v=c/λ b) λv=c c) λ=c/v d) All of the above 6 An object which has the ability to radiate the maximum possible energy for its temperature is known as a) Black body b) Thermal body
- 2. c) Emit body d)Noneof the above 7 Emissivity is defined as a) Hobject+Hblackbody b) Hobject/Hblack body c) Hblack body/ Hobject d)H black body+ Hobject 8 Є= 1 signifies that the body is a _____________ body a)Perfect black body b) Black body c)Both a and b d)None of these 9 Which of the following is an advantage of thermography testing a) The thermography device is risk as it emits radiation b) This technique is very slow c) This technique can create a thermal image d)This technique is not effective 10 Medium wave infrared is a) 8-14 µm b) 3-6 µm c) 2-3 µm d)3-5 µm 11 Long wave infrared is a) 8-14 µm b) 3-6 µm c) 10-13 µm d)8-15 µm 12 The output from the IR camera is a grey scale image .That image is also known as a) IR image b) Thermogram c) Color image d)None of the above 13 IR light has a range of wavelength that ranges from a) Red to blue b) Yellow to blue c) Red light to violet d)Red to green 14 Infrared waves ranges from a) 0.75 to 10000 µm b) 0.65 to 10000 µm c) 0.55 to 1000 µm d)0.75 to1000µm 15 Which of the following is not the basic elements of infrared detection system? a) IR detectors b) Sensor c) Optical components
- 3. d)Signal processing 16 Vibro thermographyis also known as a) Pulsed thermography b) Lock in thermography c) Modulated thermography d)ultrasound thermography 17 Stephans Law of Radiation is a) 𝐻 = 𝜎T3 b) 𝐻 = 𝜎T2 c) 𝑯 = 𝝈T4 d) 𝐻 = 𝜎T14 18 The body follows the Stephens law is termed as a) hot body b)Black body c) Both a and b d)None of these 19 In __________ thermography, a burst of ultrasonic waves are injected into the test specimen for a short time and it varies from milliseconds to few seconds. a) Modulated b) Pulsed c) Lock in d)Burst Vibro 20 The ____________ works on the basis of electromagnetic induction. a) Thermography testing b) Eddy current testing c) Vibro thermography testing d)Lock in thermography 21 Eddy currents are created through a process called a) Electrostatic induction b) Electromagnetic induction c) Both a and b d)None of the above 22 The main function of the low pass filter(LPF) is to remove _____ frequency interference noise a) High b) low 23 The main function of the high pass filter (HPF) is to remove _____ frequency interference noise a) High b) low 24 Which of the following factors are not influenced by eddy current testing? a) Permeability b) frequency c) Material conductivity d)None of the above
- 4. 25 ________ May bedefined as the ease with which a material can be magnetized. a) frequency b) Conductivity c) Permeability d)Design 26 The distance between a surface coil and the test surface is called as ________ a) Lift off b) Proximity c) Both a and b d)None of the above 27 Eddy current testing is performed within a frequency range of ________ a) 70Hz to 100MHz b) 50Hz to 100MHz c) 60Hz to 20MHz d)50Hz to 10MHz 28 ___________ are magnetic field transducer that exhibit a linear change in electric resistance under an external magnetic field. a) SQUID devices b) Hall effect sensors c)Magneto resistive sensors d) All of the above 29 ___________ can detect magnetic fields from eddy currents and can be used in eddy current testing. a) SQUID devices b) Hall effect sensors c)Magneto resistive sensors d) All of the above 30 ___________ device are designed to measure extremely weak magnetic fields. a) SQUID devices b) Hall effect sensors c)Magneto resistive sensors d) All of the above 31 A variation of eddy current testing is remote field eddy current testing is also called as a) Send probe technique b) Send- receive probe technique c) Both a and b d)None of these 32 The basic elements involved in eddy current testing system are a) Oscillator b) Test coil c) Both a and b d)None of the above 33 Skin effect impact penetration depth and the ability of eddy currents t detect defects a)True b) False
- 5. 34 ______ is theshift in time between the eddy current response from a disruption on the surface and a disruption at some distance below the surface. a) Phase lag b)Skin effect 35 What is the advantage of magneto resistive sensors? a) Expensive b) Complex in construction c) Macro size d)High sensitivity PART B 1 In Stephan’s law of Radiation ,the value of proportionality constant σ is a) 4.67x10-8 wm-2 k-4 b) 3.77x10-8 wm-2 k-4 c) 5.67x10-8 wm-2 k-4 d)6.67x10-8 wm-2 k-4 2 “A body radiates heat per unit area per unit time is proportional to the fourth power of its absolute temperature” which law states this? a) Planck’s radiation law b) Weins displacement law c) Stephan’s law of Radiation d)None of these 3 In Planks Radiation Law the value of planks constant h is a) 4.625x10-27erg-sec b) 5.625x10-27erg-sec c) 3.625x10-27erg-sec d)6.625x10-27erg-sec 4 The value of Boltzman constant k is a) 2.38x 10-16erg/°k b) 1.38x 10-16erg/°k c) 4.38x 10-16erg/°k d)3.38x 10-16erg/°k 5 ___________ law relate the fundamental electrical quantity voltage and current. a) Planck’s radiation law b) Lenz law c) Ohms law d) Weins displacement law 6 ______is one of the properties measured in eddy current testing a) Planck’s radiation law b) Lenz law c) Ohms law d) Weins displacement law 7 Which of the following is not the advantage of eddy current? a) Physical contact required b)Low cost c) Portable
- 6. d)complex shape canbe inspected 8 In __________ technique energy source are used to pulse heat the specimen surface. a) Thermography testing b) Vibro thermography testing c)Lock in thermography d) Pulsed thermography 9 In _____ technique ,the specimen surface is periodically illuminated by modulated heating source like halogen lamps ,to injet thermal waves in to the specimen. a) Lock in thermography b) Modulated thermography c) Both a and b d)None of the above 10 The application of lock in Thermography is a) Corrosion detection b) Determination of coating thickness c) Determination of impact damages on CFRP panels. d)Both a and b 11 ____________ magnetic material has a relative magnetic permeability slightly greater than 1 a) Para magnetic material b) Dia magnetic material c) Ferro magnetic material d)None of the above 12 ____________ magnetic material has a relative magnetic permeability slightly less than 1 a) Para magnetic material b) Dia magnetic material c) Ferro magnetic material d)None of the above 13 ____________ magnetic material has a relative magnetic permeability much greater than 1 a) Para magnetic material b) Dia magnetic material c) Ferro magnetic material d)None of the above 14 _______ sensor can detect magnetic fields from currents and can be used in eddy current testing a) Hall effect sensor b) Spin valve sensor c) Magnetic tunnel junction sensor d)None of the above 15 Whenever relative motion occurs between a metal conductor and magnetic lines of force ,electrical currents are induced in the surface of the metal conductor .These induced electric current called as
- 7. a) Hall effect b)Eddy currents c) Lift off d)None of the above