11. Stink damp is synonymous with A. H2S B. CH4 C. NO2 D. SO2 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
12. When the effect of surface temperature on natural ventilation will be less or negligible? A. in shallow mines B. in deeper mines C. when fan size is inadequate D. when the mine size is extensive Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
13. In ambient air of industrial area, the permissible concentration of particulate matter less than 2.5 μm size measured on 24 hours average in μg/m3 is A. 20 B. 40 C. 60 D. 100 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
14. It is the ratio of the power actually absorbed by the impeller and converted into the head of the power applied to the shaf A. volumetric efficiency B. static efficiency C. total efficiency D. mechanical efficiency Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
15. The temperatures in upcast shaft & downcast shaft are 40°C & 30°C respectively. Shaft is 350 m deep. Find the height of motive column? A. 9 B. 11 C. 13 D. 15 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
16. CO2 is treated as best extinguisher for A. class A fire B. class B fire C. class C fire D. all fires Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
17. The nature of flow of a fluid is governed by a dimensionless parameter called A. boundary layer B. reynolds number C. resistance co-efficients D. turbulent fluid Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
18. Natural ventilation can be caused by A. Auto-compression in downcast shaft B. Differences in air densities in upcast and downcast shafts C. auto-expansion in upcast shaft D. moisture content in the mine Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
19. During hard work e.g. shoveling, tramming, the metabolic heat rate (W m-2) from the body surface of an average person is in the range of A. 90 B. 150 C. 200 D. 270 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
20. Which of the following pairs is correctly matched? A. $$\frac{{BOD}}{{COD}} = 0$$ : Mine water is taxic B. $$\frac{{BOD}}{{COD}} \leqslant 0.2$$ : Acclimatization of seed is necessary C. $$\frac{{BOD}}{{COD}} \geqslant 0.6$$ : Mine water is non-biodegradable D. BOD = COD = 0 : Mine water is devoid of organic matter Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
