# How can we use various mathematical and physical constants in scipy library?

To implement Scientific or Mathematical calculation, we need various universal constants. For example, the formula to calculate area of a circle is pi*r*r where Pi is a constant having value = 3.141592653. There are various other scenarios like this where we need constants. It would really be helpful if we can incorporate these constants into our calculation with ease. The scipy.constants(), a sub-module inside the Scipy library, does the job for us and provide us a reference material to look up exhaustive list of Physical Constants, universal mathematical constants, and various units such as SI prefixes, Binary prefixes, Mass, Angle, Time, etc.

We can access the value of any constant by typing the name of the constant in scipy.constants.name_of_constant. For example, if you want to access the value of constant Pi, type scipy.constants.pi.

## Example

#Importing the module
from scipy import constants

#Printing the values of constants
print("The value of sciPy - pi = ", constants.pi)
print("The value of Golden ratio = ", constants.golden_ratio)
print("The value of Speed of light in vaccum = ", constants.c)
print("The value of Gravitational Constant = ", constants.G)
print("The value of Molar Gas Constant = ", constants.R)
print("The value of Boltzman Constant = ", constants.k)
print("The value of Proton mass Constant = ", constants.proton_mass)

## Output

The value of sciPy - pi = 3.141592653589793
The value of Golden ratio = 1.618033988749895
The value of Speed of light in vaccum = 299792458.0
The value of Gravitational Constant = 6.6743e-11
The value of Molar Gas Constant = 8.314462618
The value of Boltzman Constant = 1.380649e-23
The value of Proton mass Constant = 1.67262192369e-27