WorksheetsGas Measurement and Safety Quiz
Total questions: 40
Worksheet time: 20mins
The permissible limit of the H2S is ?
10 ppm
50 ppm
7 ppm
5 ppm
The permissible limit of the SO2 is ?
10 ppm
50 ppm
7 ppm
5 ppm
When mixed with air H2 forms on explosive mixture the limits of explosibility is ?
5 - 15
4.3 - 45
12 - 75
4 - 75
The permissible limit for the nitrous fumes is?
10 ppm
50 ppm
7 ppm
5 ppm
Methane gas is also called as?
stink damp
Marsh gas
choke damp
white damp
Methane can be found at?
roof
floor
Any place in the roadway
Exhaust gases of the locomotive
M.S.A methanometer is worked on the principle of?
Formation of gas cap
Wheatstone bridge
Infraradiation
Optical properties
Spiralaram is worked on the principle of?
Formation of gas cap
Wheatstone bridge
Infraradiation
Optical properties
Ring rose detector works on the principle of?
Formation of gas cap
Wheatstone bridge
Diffusion-combustion-contraction
Optical properties
Interferometers works on the principle of?
Formation of gas cap
Wheatstone bridge
Infraradiation
Optical
For light manual workers the wet kata is?
18
25
30
8
Ordinary U-tube manometers are not useful for measurement of gas velocities?
below 12 m/s
13 to 20 m/s
20 to 30 m/s
above 30 m/s
Geothermic gradient in Indian coal seam is....?
1 deg c per 15 m
1 deg c per 38m
1 deg c per 50 m
none
Upto what depth from the surface the temperature is constant?
10m
15m
20m
25m
The speed of the centrifugal fan is?
1 to 100 rpm
100 to 300 rpm
300 to 1000 rpm
above 1000 rpm
The mostly used blade type in centrifugal fan is?
backward
radial
forward
none
The presence of Nitrous fumes are detected by?
The rotten eggs smell
sweet smell
metallic taste on tongue
head ache
The noxious and inflammable gases of old workings of a coal mine expands when there is?
sudden rise of temperature
sudden heavy roof fall
sudden rise in barometric pressure
sudden drop in barometric pressure
For comfortable working conditions the reasonable velocity of air at the working face is?
0.5 to 2 m/s
3 to 4 m/s
5 m/s
6 m/s
Cooling power by conduction convection and radiation is given by using the ?
dry bulb temperature
wet bulb temperature
Average time of wet and dry bulbs
wet and dry bulb time and velocity of air
Inclined water gauge is used for the measurement of water gauge for?
smaller than 200 mm
greater than 200 mm
smaller than 50 mm
greater than 50 mm
The inclined water gauge can read up to?
2 mm
1.5 mm
1 mm
0.2 mm
The velocity of air flowing in a drift where the velocity pressure is 36 mm is?
36 m/s
24 m/s
42 m/s
48 m/s
In the centrifugal fan smooth flow air and conversion of velocity energy into pressure energy takes place?
In spiral casing
In the blades
At the tip of the blades
In the evasee
In the centrifugal fan reentry of the discharged air is prevented by?
spiral casing
blades
evasee
eye
With a centrifugal fan for a given quantity of air increase of efficiency of the and reduction in cost of power can be obtained with?
well designed blades of the fan
well designed spiral casing
well designed evasee
well designed eye of the impeller
The maximum permissible speed of the axial flow fan is?
8000 m/min
6000 m/min
5200 m/min
4200 m/min
The maximum water gauge developed in axial flow fan is?
10 cm
12.5 cm
13.5 cm
15 cm
The water gauge developed and quantity circulated with an axial flow fan depend on ?
Size of the fan
Shape of the blades
Design of the evasee
Speed of the blade tips
With a axial fan direction of travel of air current to the mine is changed by?
changing direction flow of air into fan by means of doors
changing the blades on the rotor
changing the direction of rotation of the motor
not possible with this type of fan
The pitch of the blades of axial flow fans is?
1 to 5 deg
5 to 10 deg
10 to 15 deg
15 to 20 deg
By varying the pitch of the blades the pressure generated by axial flow fan is?
remains same
decreases
increases
increases 8 times
The water gauge of a axial flow fan can be increased by?
increasing speed of rotation
changing the pitch of blades
installing 2 or more stages
enlarging the evasee of the fan
The manometric efficiency of axial flow fan is?
10 to 20 %
70 to 85 %
20 to 30 %
40 to 50 %
The overall efficiency of axial flow fan is?
10 to 20 %
70 to 85 %
20 to 30 %
40 to 50 %
Modern flame safety lamps can withstand an air velocity of?
5 m/s
10 m/s
15 m/s
20 m/s
The maximum air velocity at the face is?
1.7 m/s
3 m/s
5 m/s
7.5 m/s
The maximum air velocity at the main haulage roads is?
1.7 m/s
3 m/s
5 m/s
7.5 m/s
Air velocities in diesel locomotive sheds should not be less than?
4 m/s
2 m/s
1 m/s
0.75 m/s
What is the primary function of a centrifugal fan in ventilation systems?
To humidify the air
To decrease air temperature
To increase air pressure
To filter air particles
