Question

State the SI unit of pressure -
A. Newton
B. Pascal
C. Coulomb
D. Copernicus

Answer 1

Hint: Pressure is defined by the force per unit area. For example, if we are applying a force on a surface, the pressure is given by the ratio of force and the total area of the surface. Use this definition to find the dimension of pressure. You can use the basic definition or the dimension to find the unit of pressure.

Complete step-by-step answer:
Newton is the SI unit of Force.
Definition of pressure-
The pressure is the force applied perpendicularly to the surface of an object per unit area over which the force is distributed.

Hence, Pressure is given by,
$P=\dfrac{F}{A}$

The dimension of force is
$[F]=ML{{T}^{-2}}$

The dimension of the area is given by,
$[A]={{L}^{2}}$
So, the dimension of pressure is given by,
$[P]=\dfrac{ML{{T}^{-2}}}{{{L}^{2}}}=M{{L}^{-1}}{{T}^{-2}}$

SI unit of Force is Newton (N).
SI unit of length is meters (m).
So, the unit of pressure can be expressed by, $\dfrac{N}{{{m}^{2}}}$

From the dimension of pressure, we can write the unit by, $\dfrac{kg}{m{{s}^{2}}}$

However, the SI unit of pressure is given a different name.
SI unit of pressure is = Pascal
So, the correct option is (B).

Additional Information:

One of the most important units of is the Atmospheric Pressure Unit (atm).

It is equivalent to the mean sea-level atmospheric pressure on earth.

This conversion is very important -
1 atm = 101,325 Pascal

Roughly, we estimate a value of,
$1atm={{10}^{5}}Pa$
It can also be expressed in terms of mm Hg. 1 atmospheric pressure unit is equivalent to 760mm Hg pressure.
This unit is more important than the SI unit of pressure because the atmospheric pressure is measured in this unit. Forecasters use this pressure value to predict the atmosphere of a place.

Note:
As you can see there are several units of pressure available. However, most common units are ‘atm’ and ‘Pa’. Pascal is used to make mathematical calculations and ‘atm’ is used for measuring atmospheric pressure at a given place.