Q 1. Resistance of the mine gallery do not depend on
a. Velocity of air
b. Coefficient of friction
c. Area of cross section of gallery
d. Rubbing surface of gallery
Q 2. Area of rubbing surface of mine gallery is determined by
a. Perimeter of cross section÷Length of the gallery
b. Perimeter of cross section×Length of the gallery
c. π×Length of the gallery×Diameter of cross section
d. Both b & c.
Q 3. Frictional pressure drop between two points in a ventilation duct depends on
a. Velocity of air
b. Coefficient of friction
c. Area of cross section of gallery
d. All of the above
Q 4. Frictional pressure drop across two points is equal to
a. Static pressure difference between two points
b. Total pressure difference between two points
c. Velocity pressure difference between two points
d. Average pressure difference between two points
Q 5. If we smoothen the rubbing surface then resistance of the duct__________
a. Increases
b. Decreases
C. Do not change
d. None of the above