Question

How is the unit $bar$ related to the S.I unit $pascal$ ?
A. $1\;bar = {10^5}\;pascal$
B. $1\;pascal = {10^5}\;bar$
C. $1\;bar = 10\;pascal$
D. $1\;bar = 1\;pascal$

Answer 1

Hint: The unit $bar$ defines as the atmospheric pressure acted on the body or any other element. And the S.I unit $pascal$ defines as the force per unit area on the body or any other element. The unit $bar$ is related as ${10^5}$ times of the S.I unit $pascal$.

Complete step by step solution:
The unit of the pressure is expressed in different terms in different countries. In a metric unit, the unit of pressure is $bar$. But this unit is not accepted by the International system of Units. $1\;pascal$ is defined as one newton of force acting on the one-meter square area. The unit $bar$ is used to define the atmospheric pressure. It is defined as equal to ${10^5}\;pascal$, which is little bit less than average atmospheric pressure on Earth’s sea level.

Thus,
$1\;bar = {10^5}\;pascal$

Hence, the option (A) is correct.

Additional information:
Significance of pressure:
1. The high air pressure is the major reason for the evolution of living beings on the earth.
2. The flow of blood and the body fluids are forced by the pressure in the blood vessels and it helps in sustaining.
3. The water flow in the household activities and industrial activities are enforced by the pressure.
4. The conduction of the water from the roots of the plant to the vessels are conducted by the pressure.

Note: The pressure is also expressed in many terms such as kilogram-force per square centimetre, kilopond per square centimetre, gram-force, barye (dyne per square centimetre), pieze (sthene per square metre).