Laboratory experiments proved, suddenly comprising gas air mixture of containing as low as . . . . . . . . % and as high as . . . . . . . . % firedamp can be ignited and made explosive both the temp. and pressure raised simultaniously.

Which of the following prime characteristic the nonel blasting has?

A. It has greater shock to the surrounding

B. It is noiseless in character

C. It has tremendous effect on explosive column

D. It can not be used in a place where there is a chance of stray current

The main purpose of self rescuer is to enable the wearer to escape through an atmosphere resulting after a . . . . . . . . or after an . . . . . . . . in a mine.

A. Fire, Explosion

B. Gas, Outburt

C. Rockburst, bump

D. None

Cyclone, bag filter and scrubber can be used for control.

A. Water pollution

B. Soil pollution

C. Air pollution

D. Noise pollution

A two phase system in which an inner or dispersed phase is distributed in an outer called

A. Emulsion

B. Slurry

C. Explosion

D. Erosion