131. Addition of _______________ to steel does not help in improving its machinability ?

A. Sulphur
B. Silicon
C. Lead
D. Phosphorous

132. Brass parts with high residual tensile stress at the surface are susceptible to season cracking (i.e. spontaneous cracking occurring on exposure to atmospheric corrosion), if its zinc percentage is more than?

A. 5
B. 10
C. 20
D. 35

133. Alloying elements present in Haynes stellite, which has superior performance than high speed steel, are____________________?

A. Nickel, cobalt & chromium
B. Tungsten, chromium & cobalt
C. Manganese, chromium & cobalt
D. Tungsten, molybdenum & nickel

134. _______________ test can be termed as the semi-destructive test?

A. Impact
B. Torsion
C. Hardness
D. Charpy

135. Dowtherm is a____________________?

A. High-temperature heating medium (a petroleum product)
B. Product of coal tar distillation
C. Very heat-sensitive material
D. None of these

136. Boiler tube size is specified by its thickness and _____________________ diameter ?

A. Outside
B. Inside
C. Mean
D. None of these

137. Boiling point of water gets lowered at high altitudes (e.g., hills), because ___________________?

A. Temperature is low
B. Atmospheric pressure is low
C. Atmospheric pressure is high
D. None of these

138. The leaching solvent used in Baeyer’s process for the purification of bauxite is___________________?

A. Ammonium hydroxide
B. Sodium carbonate
C. Sodium hydroxide
D. Ammonium carbonate

139. With an increase in annealing temperature, the following defect density decreases?

A. Vacancy
B. Dislocation
C. Grain boundary
D. All of these

140. A gas which is collected over water becomes moistened due to water vapour, exerts its own partial pressure at the gas temperature, which is termed as its_______________?

A. Aqueous tension
B. Saturated humidity
C. Vapor pressure
D. Absolute humidity