Practice Test: Question Set - 40
1. Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.
- (A) Atoms
- (B) Neutrons
- (C) Nucleons
- (D) Electrons
2. The approximate height of a blast furnace having a useful volume of 2000 m3 is about __________ meters
- (A) 25
- (B) 35
- (C) 55
- (D) 75
3. Which of the following mainly decides the current to be employed is arc welding?
- (A) Electrode size
- (B) Plate thickness
- (C) Voltage across the arc
- (D) Welded portion length
4. Main constituent of bone ash is
- (A) Ammonium phosphate
- (B) Calcium phosphate
- (C) Animal charcoal
- (D) Ammonium sulphate
5. Probability of cavitation occurring becomes very high, when the local __________ resulting in water bubbles formation, which on rupture cause cavitation
- (A) Pressure falls below the vapor pressure
- (B) Pressure becomes very high
- (C) Temperature becomes low
- (D) All 'a', 'b' & 'c'
6. Isotropic materials have the same __________ in all directions.
- (A) Induced stresses
- (B) Density
- (C) Elastic properties
- (D) Thermal properties
7. In the diving apparatus, helium is used along with oxygen, because it is
- (A) Easily available
- (B) Not soluble in blood at high pressure
- (C) Lighter than nitrogen
- (D) Completely miscible with oxygen
8. Projection welding & stud welding is categorized as the __________ welding.
- (A) Pressure
- (B) Thermit
- (C) Resistance
- (D) Arc
9. Water hammer is caused in steam carrying pipelines, because of
- (A) Partial condensation of steam
- (B) Vibration of the pipeline
- (C) High degree of superheat of steam
- (D) Its exposure to torrential rain
10. The following thermocouple may be used for measuring temperature upto 1873°K.
- (A) Chromel-alumel
- (B) Copper-constantan
- (C) Platinum-platinum rhodium
- (D) Iron-constantan
11. Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process?
- (A) Galvanizing
- (B) Tinning
- (C) Sherardizing
- (D) None of these
12. Drossing is a __________ operation.
- (A) Smelting
- (B) Dressing
- (C) Roasting
- (D) Pressing
13. The underground well of a biogas plant is called the
- (A) Septic tank
- (B) Oxidation well
- (C) Digestor
- (D) Lagoon
14. Lead pencil contains
- (A) Graphite
- (B) Lead sulphide
- (C) Lead
- (D) Both (b) & (c)
15. A fire tube boiler is limited to a maximum steam pressure of about __________ kg/cm2.
- (A) 6
- (B) 18
- (C) 38
- (D) 52
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