Question

Which is the most accurate instrument to measure pressure and is used as a standard?
A. Aneroid Barometer
B. Mercury Barometer
C. Barograph
D. Manometer

Answer 1

Hint:In most cases the hydrostatic pressure induced by the weight of the air above the measuring point is roughly approximated to the atmospheric pressure. With increased height, the atmospheric mass decreases, therefore reducing atmospheric pressure with increased elevation. Pressure measurement force per unit area, SI pascal units (1 pascal = 1 newton per \[{m^2}\]).

Complete answer:
A barometer is a scientific tool used in particular environments to measure air pressure.Pressure trends can predict short-term weather changes. Many air pressure measures are utilised to locate surface troughs, pressurised systems and frontal borders in surface weather analysis.

Barometers (the most basic and frequent form of altimeter) and pressure altimeters are fundamentally the same instrument, although they are used for different reasons. An altimeter is designed to be utilised at different levels that match the corresponding air pressure with the elevation, whereas a barometer is maintained at the same level and measures small variations in weather pressure.

A barometer of mercury is an appliance for measuring atmospheric pressure at a certain place. The barometer is made out of a vertical glass tube closed at one end. The closed end is on the top and is located in the bottom of the mercury basin. The pressure gauge is absolute. Long, hollow and vertical glass tube in the mercury air is evacuated.

Also known as the Torricellian Barometer is a mercury barometer. The atmospheric pressure is measured by the mercury adjustment of the tube until the weight of a mercury column balances the atmospheric force on the tank.

Hence option B is correct.

Note:The air pressure balances a column of mercury with an accurate measurement of its height on the mercury barometer. Mercury barometers are routinely calibrated for environmental temperature and the local gravitational value in order to boost their accuracy.