Question

1 bar is equal to how many pascals?
A) ${10^4}$
B) ${10^5}$
C) ${10^6}$
D) ${10^7}$

Answer 1

Hint: Both the units are to measure the pressure. We define pressure as the force applied perpendicular to the surface of an object per unit area over which that force is distributed. To understand the relationship between two units first we will understand each unit individually.

Complete answer:
First let us understand what a bar is. A bar is a unit of pressure. This is assumed that 1 bar is almost equal to the 1 atmospheric pressure. This amount of pressure measured in this unit can be converted into a standard unit system. $1bar = 1kg/m{s^2}$ and $1bar = 100000N/{m^2}$ .
Pascal is also a unit of pressure. It is generally denoted by $Pa$. This is a SI derived unit of pressure. The pascal can be expressed using SI derived units, or solely SI base units, as \[1Pa = 1N/{m^2} = 1kg/m{s^2}\] . Where N is the newton, m is the meter, kg is the kilogram, and s is the second.
Now if you observe the above two steps that $1bar = 100000N/{m^2}$ and \[1Pa = 1N/{m^2}\] , then we can say that $1bar = 100000Pa$ or $1bar = {10^5}Pa$ .

Hence the correct option is option B.

Note: The system of the unit we use to measure things like time, distance, force, length, etc. is very important to solve real-life problems. When we deal with a problem then we use all the quantities in the same unit system. If we are using say pressure in Pa then we will get the result in the system of the unit to which Pa belongs to. Therefore we cannot use a different unit for the same type of quantities. For example, if we are using the length of two different rods in a formula then both the quantities should be in the same unit whether it is centimeter or meter.