41. A fan ventilating a heading through a duct of 750mm diameter circulates 5m3s-1 of air at the face. Calculate the heat added to the air by the fan, if the input power of the fan is equal to 3kW. A. 1667 J B. 2617 J C. 2917 J D. 3317 J 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
42. Find the percentage of blackdamp from the mine air sample (pressure by volume) shown below: O2 = 19.11; N2 = 79.04; CO2 = 0.25; CO = 0.02; CH4 =1.58 A. 6.1 B. 7.1 C. 8.1 D. 9.1 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
43. The method factor for anemometer reading in duct varies with the A. roughness of the sides of the airway and the Reynold's number B. length of the duct C. velocity of air flowing through the duct D. quantity of air flowing through the duct 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
44. What is the acoustical power of a 100 hp air compressor whose rated sound power level is 130 dB A. 13 W B. 9 W C. 10 W D. 12 W 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
45. What do you mean by head co-efficient? A. It is the ratio of the head at the operating point to Euler's head at zero capacity B. It is the ratio of the square of the impeller speed to power input C. it is the ratio of the head developed to the square of the speed D. it is the ratio of the speed to the Euler's head at maximum efficiency 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
46. Electrostatic precipitator works on the principle of A. Capacitance change B. Ionisation of the particles C. Electro heating of gases D. Centrifuging the gaseous molecules 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
47. Noise in fans is a function of A. Where A is given by A. rotational speed B. fan blade number C. quality of air velocity D. fan stator 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
48. As per Indian law the methane concentration should not exceed "A%" in any part of the mine. A is given by A. 0.5% B. 0.75% C. 1% D. 1.25% 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
49. What are the composition of the solution in which the plates of the Oldham cap lamp battery remain immersed? A. HNO3 + HCL B. HCL + H2O C. H2SO4 + distilled water D. Lead solution 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
50. In ambient air of an School locality, the permissible concentration of PM10 measured on 24 hours average in μg/m3 is A. 50 B. 150 C. 75 D. 100 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
