866. Specific __________ is a dimensionless quantity.
A. Heat
B. Humidity
C. Weight
D. None of these
✅ The correct answer is option D.
869. The ratio of thermal & electrical conductivity is same for all the metals at the same temperature ; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K)
A. T
B. 1/T
C. T²
D. 1/T²
✅ The correct answer is option A.
872. Which is the most lethal weapon ?
A. Atom (fusion) bomb
B. Hydrogen bomb
C. Cobalt bomb
D. Neutron bomb
✅ The correct answer is option C.
875. In the acid Bessemer process, the hot metal should have the following com-positon.
A. S < 0.05% and P < 0.05%
B. S < 0.05% and P < 1.5%
C. S < 0.05% and P > 1.5%
D. S > 1.5% and P < 0.05%
✅ The correct answer is option A.
878. Which of the following phenomenon/ phenomena is/are diffusion controlled ?
A. Dislocation climb
B. Cross-slip
C. Twinning
D. Recrystallisation
✅ The correct answer is option D.
881. For the Stoke’s law to be valid in the case of a falling sphere in a fluid, the
A. Reynolds number (based on sphere diameter) should be < 1
B. Flow around the sphere should be in turbulent region
C. Sphere must be metallic
D. Fluid density should be constant
✅ The correct answer is option C.
884. For hardening high alloy steel, it is to be heated slowly and uniformly to avoid
A. Local hardening
B. Scale formation
C. Segregation
D. Warpage
✅ The correct answer is option D.
887. Annealing of cast iron
A. Softens it to facilitate machining
B. Decreases the free carbon
C. Increases the strength
D. None of these
✅ The correct answer is option A.
847. Other parameters remaining same, the recrystallisation temperature of an alloy is lowered, when
A. Strain rate is increased
B. Grain size is increased
C. Prior cold deformation is increased
D. Not affected by any of the above parameters
✅ The correct answer is option A.
850. Production of one ton of steel plate in a modern integrated steel plant in India consumes about __________ kWh of electricity.
A. 50
B. 250
C. 450
D. 850
✅ The correct answer is option C.