Mine Ventilation MCQs Questions & Answers | Mining Engineering

An aneroid barometer is a type of barometer that doesn't use liquid to measure atmospheric pressure.
It uses a small, flexible metal box called an aneroid cell.
This box is partially evacuated (air removed), so changes in atmospheric pressure cause it to expand or contract.
These movements are mechanically amplified and displayed on a dial to indicate the pressure.

Since it relies on a mechanical system and not a liquid column, the answer is "None".
Options A (Mercury), B (Water), and C (Petrol) are all liquids but are not used in aneroid barometers.
Mercury is used in mercury barometers, which is a different type of barometer.

To find the critical pressure of the booster fan, we can use the equation:
Combined Resistance = Surface Fan Pressure + (Booster Fan Pressure / Flow Quantity)

Given:
Resistance of Split A = 0.35 Ns²m^-8
Resistance of Split B = 0.05 Ns²m^-8
Combined Resistance = 0.4 Ns²m^-8
Surface Fan Pressure = 1000 Pa (constant)
Flow Quantity through Split A (without booster fan) = Resistance of Split A / Surface Fan Pressure
Flow Quantity through Split A = 0.35 Ns²m^-8 / 1000 Pa = 0.00035 m³/s
Flow Quantity through Split B = Resistance of Split B / Surface Fan Pressure
Flow Quantity through Split B = 0.05 Ns²m^-8 / 1000 Pa = 0.00005 m³/s

Now, using the combined resistance equation, we can calculate the critical pressure of the booster fan (let's denote it as Pb):
Combined Resistance = Surface Fan Pressure + (Pb / Flow Quantity through Split A)

0.4 Ns2m-8 = 1000 Pa + (Pb / 0.00035 m3/s)

Now, solve for Pb:
Pb = 0.4 Ns2m-8 - 1000 Pa * (1 / 0.00035 m3/s)
Pb = 0.4 Ns2m-8 - 2857.14 Pa
Pb = 875 Pa

Therefore, the critical pressure of the booster fan is 875 Pa