75. Which of the following accounts for maximum loss of energy in a coal fired boiler?
A. Incomplete combustion of fuel
B. Outgoing flue gases
C. Radiation heat losses
D. Unburnt carbon in ash
✅ The correct answer is option B.
77. A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalant bonds resulting in __________ electrons.
A. Lack of free
B. Excess of
C. Decrease in
D. None of these
✅ The correct answer is option B.
79. Alloy powder manufactured by the following process have spherical shapes.
A. Electrochemical deposition
B. Gaseous reduction
C. Atomisation
D. Mechanical attrition
✅ The correct answer is option C.
81. Current employed in resistance welding ranges from __________ kVA/cm² .
A. 1.2 to 2.5
B. 4.5 to 6.2
C. 7.5 to 8.5
D. 10.5 to 15.5
✅ The correct answer is option B.
83. In a good rimming steel
A. Carbon and silicon should be low
B. Silicon should be low but carbon should be high
C. Both silicon & carbon should be high
D. Silicon should be high but carbon should be low
✅ The correct answer is option A.
85. A simple closed grinding circuit may consist of
A. A ball mill and a classifier
B. A rod mill and a hydrocyclone
C. A jaw crusher and a hydrocyclone
D. A ball mill and a froth floatation cell
✅ The correct answer is option A.
87. Normalising does not __________ of a metal.
A. Improve machinability & tensile strength
B. Remove internal stresses
C. Refine the structure
D. Remove strains caused by cold working
✅ The correct answer is option B.
89. Which of the following is not a principal alloying element for the structural steel?
A. Molybednum
B. Nickel
C. Manganese
D. Chromium
✅ The correct answer is option A.
92. Stresses encountered in the metal forming processes are less than the __________ of the material.
A. Fracture strength
B. Yield strength
C. Elastic limit
D. Limit of proportionality
✅ The correct answer is option A.
95. What is the percentage of chromium in 18-4-1 high speed steel?
A. 1
B. 4
C. 18
D. 23
✅ The correct answer is option C.