A. Copper
B. Nickel
C. Aluminium
D. Gold & silver
Related Mcqs:
- The thickness of oxide film is y at time t. If K1, K2 and K3 are the temperature dependent constants, the parabolic law of oxidation is given by __________________?
A. y2 = 2k1t + k2
B. y = k1 ln (k2t + k3)
C. y = k1 t + k2
D. y = k1t3 + k2 - Oxide layer formed on the non-ferrous metal surface after its annealing is__________________?
A. Removed by acid pickling
B. Hammered into the surface
C. Removed with coarse emery cloth
D. Left as such to protect the surface - _____________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C ?
A. Veneering
B. Galvanising
C. Electroplating
D. Calorising - The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the ‘Curie temperature’. Its value for cobalt is ______________ °C?
A. 768
B. 1127
C. 1359
D. 1480 - For infinite parallel planes having emissivities ε1 & ε2, the interchange factor for radiation from surface 1 to surface 2 is given by__________________?
A. (ε1 + ε2)/ε1.ε2
B. ε1.ε2/(ε1 + ε2 – ε1.ε2)
C. ε1.ε2
D. ε1 + ε2 - Insulation of liquid surface can be achieved by _____________ on top of its surface?
A. Floating hollow polypropylene spheres
B. Spraying alumina powder
C. Putting cement
D. None of these - Alumina, silica, lime and iron oxide are the basic raw material for the manufacture of Portland cement. The component of Portland cement which first hardens is_____________________?
A. 5CaO. 3 Al2O3
B. 3CaO. Al2O3
C. 3CaO. SiO2
D. 2CaO. SiO2 - _______________ is the hardest oxide and is hence used where high wear resistance at high temperature is required?
A. Beryllium
B. Zirconia
C. Alumina
D. Magnesia - _______________ is a non volatile film forming constituent of a paint ?
A. Thinner
B. Dryer
C. Drying oil
D. None of these - The malleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the maximum malleability ?
A. Lead
B. Copper
C. Aluminium
D. Wrought iron
