A man exhales 0.002 m³ of CO₂ per min when working in a confined space in underground. Assuming that the fresh air contains 0.03% CO₂, the minimum quantity of fresh air to be supplied per person in m³/min, so that concentration of CO₂, in air never crosses 0.4%, will be

The liquid employed in aneroid barometer.

The mechanical mixture of gases existing in a mine given off after explosion called

A Drager Gas Mask does not filter

The resistances of two splits A and Bare 0.35 Ns²m^-8 and 0.05 Ns²m^-8 respectively. The combined resistance of the shafts and trunk airways is 0.4 Ns²m^-8. A booster fan is planned to be installed in split A to increase the quantity flowing through it. Assuming that the surface fan continues to operate at a constant pressure of 1000 Pa, the critical pressure of the booster fan in Pa is