Question

Which instrument is used to measure atmospheric pressure?
A. Barometer
B. Calorimeter
C. Thermometer
D. Speedometer

Answer 1

Hint: To know which instrument is used to measure the atmospheric pressure we must first discuss about the atmospheric pressure. Atmospheric pressure is simply the force per unit area exerted against a surface by the weight of the air above that particular surface. We know that atmospheric pressure gradually changes with the distance above or below the sea level so we need an instrument to measure it.

Complete Step-by-Step solution:
We need an instrument that lets us know whether or not atmospheric pressure is rising or falling. In the early 17th century, many Italian miners were puzzled by the fact that their water pumps would not raise the water after a given height. So, Galileo and other scientists observed and created a theory that some sort of suction raised the water but also stated that the force could only raise the water so high.
Barometer is a device that can measure the atmospheric pressure based on the weight of the air column. It was invented by the Italian scientist Evangelista Torricelli, who studied the properties of mercury in a vacuum and successfully developed the first barometer. Barometer works by balancing mercury weight in the glass tube over the weight of atmospheric pressure. Barometer is also used to measure the weather patterns.
Hence, we can say that a Barometer is the instrument that is used to measure the atmospheric pressure.
$\therefore$ Option A. Barometer is the correct answer.

Note- In such types of questions, just keep in mind that we have to focus on atmospheric pressure here and after knowing that just focus on the fact which characteristic we have to measure and then arrive at the answer that the barometer is the device that is used to measure the atmospheric pressure. Also, there are two main types of barometers i.e. Mercury, Altimeter and Aneroid barometer.