1.
How the anemometer is used to determine the average velocity of air?

4.
A high volume air sampler is operated for 8 hrs in a mine with the flow rate of air varying from 1.5 m3/min to 1.3 m3/min. The empty weight of the filter paper is 2.30 g and the final weight is 2.65 g. The mean concentration of the suspended particulate matter (SPM) during the study period in μg/m3 is

6.
The primary aim of ventilation control in the event of fires is

7.
The curvature of diffuser vane shall be so fixed that the fluid enters the guide passage with minimum loss. This is possible only when

9.
What should be minimum quantity of air to be circulated along a long wall face at its maximum speed of 7.5m for a 3m thick gassy seam of 3rd degree?