The question asks about the primary function of a barometer. We need to recall the definitions and applications of common meteorological instruments.
Correct Option: C) Atmospheric pressure
The question asks about the common substance used in barometers. Barometers are instruments used to measure atmospheric pressure. The choice of substance is crucial for accurate and practical measurement.
C) Mercury is the correct answer because its high density, low vapor pressure, and non-wetting properties make it ideal for measuring atmospheric pressure in barometers.
The question asks about the primary function of a manometer. We need to recall the basic principles and applications of manometers in fluid mechanics.
C) Pressure difference between two points. Manometers, especially differential manometers, are specifically designed and widely used to measure the difference in pressure between two points in a fluid system. The height difference of the liquid column in the manometer directly corresponds to this pressure difference.
To determine the factors affecting the pressure exerted by a column of liquid, we need to recall the formula for hydrostatic pressure. This formula directly relates pressure to certain physical properties of the liquid and the column itself.
Correct Option: C) Its height
The question asks for the typical unit used to express atmospheric pressure at sea level. We need to identify the standard unit commonly employed for this purpose in scientific and meteorological contexts.
B) atm is the standard unit specifically defined as the average atmospheric pressure at sea level. It serves as a reference point for pressure measurements.
Pascal is defined as?
The question asks for the definition of Pascal, which is the SI unit of pressure. We need to recall the formula for pressure and the corresponding SI units for force and area.
Correct Option: A) N/m 2
This option correctly represents the definition of Pascal as Newton per square meter, which is the SI unit of pressure.