CWB 2 Module 18 Questions well answered

CWB 2 Module 18 Questions True or False? X-rays are a type of electromagnetic wave but gamma rays are beams of tiny charged particles." - correct answer False List three disadvantages of radiography over other inspection methods. - correct answer Bulky equipment, Special safety precautions, some defects not reliably detected The effect of increasing the voltage (kV) in an X-ray machine is to: A) Increase the X-ray beam intensity without changing its wavelength B) Decrease the intensity and shorten the wavelength C) Increase the intensity and shorten the wavelength - correct answer C) Increase the intensity and shorten the wavelength Do gamma rays generally have a greater or lesser ability to penetrate thick steel then X-rays. - correct answer Greater List three disadvantages of gamma rays over X-ray radiography. - correct answer Radiation is emitted continuously, Radiation hazard, Cannot be used on all materials (Aluminum), Radiographic contrast generally less than X-rays For a given intensity of X-rays striking a specimen, what are the two main factors that affect the intensity that emerges fro the specimen to strike the film. - correct answer Thickness and type of material Which of the following conditions gives the better image contrast? A) A low energy level with a adequately long exposure time B) A high energy level with a shorter exposure time - correct answer A) A low energy level with a adequately long exposure time Place the following in order of increasing absorption of X-rays: A) Steel B) Tungsten C) Welding Slag - correct answer Welding Slag, Steel, Tungsten True or False? The only thing that causes fuzziness at the edge of an image is geometric unsharpness - correct answer False, fuzziness is also caused by inherent unsharpness and scattering List the three dimensions that affect geometric unsharpness and the relationship among them (equation) - correct answer Source size, F; object-to-source distance, d; thickness, t Ug = Ft/d What is the simplest way to reducing the geometric unsharpness for a given plate and x-ray machine? - correct answer Increase the object (plate) to source distance True or False? The purpose of the IQI is to verify that all defects greater than 2% of the plate thickness have been detected. - correct answer False What features of the IQI image must be clearly distinguished on the radiograph when using X-ray. - correct answer Outline of the IQI and the 2T hole If it is not possible to place the IQI on the source side of the specimen, what can be done? A) Place the IQI on the film side but reduce the IQI by one size B) Place the IQI on the film side and use the same IQI size as you would on the source side C) Nothing, you cannot take a radiograph unless the IQI is on the source side - correct answer A) Place the IQI on the film side but reduce the IQI by one size Some dark crack-like indications appear on a radiograph. If they are not due to cracks in the actual specimen what else could the result from? - correct answer Scratches or cracks in the lead intensifying screens What is the specified range of density of a radiograph according to most codes? - correct answer 1.5 to 3.5 True or False? Since radiography is a volumetric method the condition of the surface is not an important factor - correct answer False How would you distinguish spatter from porosity of a radiography. - correct answer Spatter appears white or light and may cover the base metal as well as the weld. Porosity is normally confined to the weld metal and appears dark. True or False? Radiography is not recommended by CSA W59 for fillet welds. - correct answer True Which of the following defects could most likely be missed by radiography? A) A crack B) Porosity C) Slag inclusions - correct answer A) A crack