In the diving apparatus, helium is used along with oxygen, because it is ____________________?

Related Mcqs:

1. Melting point & boiling points of liquid oxygen are respectively – 218.8°C & – 183°C, while the same for liquid nitrogen is – 210°C & – 195.8°C respectively. The difference in melting points of liquid oxygen & liquid nitrogen is not equal to 8.8 ?

   A. °C
   B. °F
   C. °K
   D. °R

2. Volumetric composition of flue gas analysed with the Orsat apparatus is : CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that_________________?

   A. Pure oxygen has been used for combustion
   B. Nitrogen percentage in the fuel is very high
   C. Excess air has been used for combustion
   D. Hydrogen is not present in the fuel

3. Oxygen cylinders used for autogenous (cutting/welding) purposes are ___________________?

   A. Seamless & made of steel
   B. Heat treated before use
   C. Made by sand casting
   D. Welded steel cylinders

4. Theoretical volume of oxygen required for complete combustion of 1Nm3 of acetylene, in oxy-acetylene welding is ______________ Nm3 ?

   A. 0.5
   B. 1
   C. 1/3
   D. 2.5

5. Powder metallurgy technique is used in the production of ____________________ tools ?

   A. Tungsten carbide
   B. High carbon steel
   C. High speed steel
   D. Drilling

6. ____________________ of hard alloy and tool steel is done to make it easily machinable ?

   A. Case carburising
   B. Tempering
   C. Normalising
   D. Annealing

7. One ton of refrigeration is not equivalent to the heat removal rate of ____________________?

   A. 200 BTU/minute
   B. 50 kcal/minute
   C. 50 kJ/sec
   D. 3.5 KW

8. Out of the following, the lowest packing of atoms exists in ____________________ crystal lattice structure?

   A. Hexagonal close, packed (hcp)
   B. Face centred cubic (fcc)
   C. Body centred cubic (bcc)
   D. Simple cubic

9. Constituents of stellite are ____________________?

   A. Zinc, copper & nickel
   B. Cobalt, chromium & tungsten
   C. Zinc, aluminium & nickel
   D. Nickel, cobalt & vanadium

10. Blow off cock is provided in steam boiler to ____________________?

    A. Guard the boiler in case of abnormal rise in steam pressure
    B. Drain out water and sludge during its repair
    C. Regulate the supply of water in boiler
    D. Put out the fire in the furnace when the water level in the boiler falls to unsafe limit