1159. Materials having resistivity ranging from 1 to 100 ohm. cm is termed as
A. Conductor
B. Insulator
C. Semi-conductor
D. None of these
✅ The correct answer is option C.
1162. When metals are heated to high temperature, their __________ increases in general.
A. Atomic vibration
B. Creep strength
C. Yield stress & ultimate tensile strength
D. Toughness & stiffness
✅ The correct answer is option A.
1165. Which of the following alloying elements is present in maximum percentage in high speed steel.
A. Molybdenum
B. Chromium
C. Tungsten
D. Vanadium
✅ The correct answer is option A.
1092. Eutectic reaction for iron-carbon system occurs at a temperature of __________ °C.
A. 723
B. 959
C. 1147
D. 1493
✅ The correct answer is option A.
1095. The efficiency of a Carnot heat engine operating between absolute temperatures T₁ and T₂ (when, T₁ > T₂) is given by (T₁ – T₂)/T₁. The co-efficient of performance (CO.P.) of a Carnot heat pump operating between T₁ and T₂ is given by
A. T₁/(T₁-T₂)
B. T₂/(T₁-T₂)
C. T₁/T₂
D. T₂/T₁
✅ The correct answer is option B.
1098. Notched bar test is used for testing the __________ of a material.
A. Impact strength
B. Endurance limit
C. Machinability
D. Corrosion resistance
✅ The correct answer is option A.
1101. Deformation band is absent in materials having __________ lattice crystal structure.
A. Fcc
B. Bcc
C. Hcp
D. None of these
✅ The correct answer is option C.
1104. Which of the following does not lower the surface tension of liquids ?
A. Fat
B. Soap
C. Detergent
D. Surfactant
✅ The correct answer is option A.
1107. Heat transfer by radiation from a hot body will be most rapid, if its surface is __________ because of its higher emissivity.
A. White & rough
B. Black & rough
C. White & polished
D. Black & polished
✅ The correct answer is option B.
1110. When water is sprayed on air, passing through an insulated chamber maintained at a temperature higher than the dew point of entering air but lower than its dry bulb temperature, then the air is
A. Cooled and dehumified
B. Heated and humidified
C. Cooled and humidified
D. Heated and dehumidified
✅ The correct answer is option C.