Pick out the wrong statement?
(A) Copper is the metal having the highest electronic conductivity
(B) Hardenability & Weldability of metals are inversely related
(C) Covalent bonding formed by sharing of electrons is present in all semi-conductor materials
(D) Glass transition temperature applies to ‘polymers’ but not to ‘glasses’
Pick out the wrong statement about the machinability of metals. Machinability of a metal ?
(A) Decreases with increase in strain hardening tendencies
(B) Decreases with increase in hardness, in general
(C) Depend on the composition, microstructure and physical & mechanical properties
(D) Decreases with increases in tensile strength & decrease in grain size
Which of the following is not a ferromagnetic material ?
(A) Nickel
(B) Cobalt
(C) Aluminium
(D) Iron
Increasing the carbon content of steel_________________?
(A) Reduces the upper shelf energy
(B) Increasing the ductility transition temperature
(C) Decreases brittleness
(D) Decreases hardness
Dislocation cross-slip is difficult in those materials, which have___________________?
(A) Large number of slip systems
(B) High work hardening rate
(C) Coarse grain size
(D) Low stacking fault energy
In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is ______________ °C?
(A) 20
(B) 60
(C) 120
(D) ∞
For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be _________________ toys ?
(A) 250
(B) 500
(C) 1000
(D) 3000
A solid aluminium ball, when quenched in a water bath maintained at 40°C, cools down from 550°C to 450°C in 20 seconds. The expected temperature of the ball after next 20 seconds may be about ____________________ °C?
(A) 370
(B) 340
(C) 320
(D) 300
Spark plug is provided in a/an_________________?
(A) Engine having carburettor
(B) Diesel engine
(C) Compression ignition engine
(D) Both
Pick out the correct statement about the condensation?
(A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation
(B) Suitable coating or vapour additive is used to promote film wise condensation
(C) If a condensing liquid does not wet the surface dropwise, even then condensation will take place on it
(D) Reynolds number of condensing liquid is based on its mass flow rate