61. Match the followings:
Component of flame safety lamp
Purpose of component
P. Asbestos ring
1. Dissipation of heat of flue gas
Q. Wire gauges
2. Formation of air-tight joints
R. Outer glass
3. Arrest of explosion inside the lamp
S. Combustion chimney
4. Separation of inlet air from flue gas
| Component of flame safety lamp | Purpose of component |
| P. Asbestos ring | 1. Dissipation of heat of flue gas |
| Q. Wire gauges | 2. Formation of air-tight joints |
| R. Outer glass | 3. Arrest of explosion inside the lamp |
| S. Combustion chimney | 4. Separation of inlet air from flue gas |
62. Proximate analysis of 50 g of a coal sample shows the following:
Moisture = 0.80 g
Ash = 7.85 g
Volatile matter = 15.90 g
The fixed carbon in percentage on a dry, ash free basis is
Moisture = 0.80 g
Ash = 7.85 g
Volatile matter = 15.90 g
The fixed carbon in percentage on a dry, ash free basis is
63. A pitot tube is inserted in a ventilation duct with the nose facing the air flow. A vertical U-tube manometer filled with alcohol (specific gravity 0.8) has been used for pressure measurements such that 10.2 mm is read as the total pressure and 8.8 mm as the static pressure. Given the density of air to be 1.2 kg/m3, the air velocity at the nose of the pitot tube in m/s is
64. Oxygen flow rate in the self contained breathing apparatus Proto Mark IV is
65. A toxic gas flows into a mine working place at the rate of 2.52 m3/min. The concentration of the gas in the intake air is 0.25%. The minimum quantity of intake air in m3/min required to dilute the gas to its threshold limit value of 1.0% is
66. A flammable mixture has 70% CH4 and 30% CO. The lower flammability limits for these gases are 5% and 13% respectively. For the mixture, the lower flammability limit in % is
67. Given the following,
Equation/formula/law
Application
P. Bernoulli equation
1. Pressure loss in laminar flow of fluid
Q. Poiseuille equation
2. Drag loss due to regular obstructions in fluid flow
R. Bromilow's formula
3. Energy conservation in ideal fluid flow
S. Stokes law
4. Terminal settling velocity of fine particles
in fluid
the correct match is
| Equation/formula/law | Application |
| P. Bernoulli equation | 1. Pressure loss in laminar flow of fluid |
| Q. Poiseuille equation | 2. Drag loss due to regular obstructions in fluid flow |
| R. Bromilow's formula | 3. Energy conservation in ideal fluid flow |
| S. Stokes law | 4. Terminal settling velocity of fine particles in fluid |
the correct match is
68. A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns2m-8 and 3.2 Ns2m-8, respectively as shown in figure. Trunk airways have resistance of 0.2 Ns2m-8. The main mine fan is generating pressure of 500 Pa.
The flows in the two splits are equalized by placing a booster fan in split B. Assume that the fan pressure does not change after installation of the booster fan. The size of the booster fan in Pa is
The flows in the two splits are equalized by placing a booster fan in split B. Assume that the fan pressure does not change after installation of the booster fan. The size of the booster fan in Pa is
69. Pressure characteristic of a mine fan is given by. P = -0.06Q2 + 400. where P is the pressure in Pa and Q is the quantity in m3/s. The resistance of the mine is 0.19 Ns2/m8. An identical fan is installed in the mine to operate in series with the existing fan. The new mine quantity in m3/s is
70. For Indian coal mines, the 'maximum allowable concentration' of respirable dust containing 7.5% free silica in mg/m3 is
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