CWB LEVEL 3 MODULE 20 PRACTICE EXAM QUESTIONS AND ANSWERS GRADED A+ 100% VERIFIED.

1. Which of the following metals has the highest thermal conductivity? C



(a) carbon steel



(b) stainless steel (



(c) aluminum ANS >>> (c) aluminum
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, 2. The Ellingham diagram C



(a) is a plot of thermal conductivity against temperature.



(b) shows the free energy of oxide formation against temperature.



(c) shows the rate of oxidation of metals against temperature. ANS >>> (b)
shows the free energy of oxide formation against temperature.



3. True or False?



A metal with a high negative free energy of oxide formation will generally
require



greater shielding from the atmosphere during welding. ANS >>> True



4. Electricity can be conducted by ANS >>>



(a) atoms and electrons.



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, (b) electrons and ions. C



(c) only ions. ANS >>> (b) electrons and ions. C



5. Which of the following elements is often present in submerged arc fluxes
to improve arc



stability?



(a) copper (



(b) potassium (



(c) nickel C



(d) tungsten ANS >>> (b) potassium (



6. Thoria is added to tungsten electrodes for what purpose? ANS >>> To
increase thermionic emission by lowering the work function.



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