Physical world , Fundamental forces

• PHYSICAL WORLD:: The term physical world refer to all things present in nature. Like as - Atoms , matter, sound, Radiation etc. 

• FUNDAMENTAL FORCE:: In the physical world exist only four fundamental force, the term fundamental represents the nature. We can define fundamental force as a law of physics and base of universe.

There are four fundamental forces, 

1. Gravitational force
2. Electromagnetic force
3. Weak nuclear force 
4. Strong nuclear force

♦ Gravitational force:: 

• This force works between mass object.
• The nature of this force is always attractive.
• This force introduced by sir "NEWTON" 
• The range of this force is infinite.
• This force is directly proportional to product of two mass , those have interacting by gravitational interaction by separation r. 
• This force is inversely proportional to the square of seperation between them

                                        F∝mM -------------(1)

  F∝1/r² ---------(2)

          From equation (1) and (2) 

                              F∝mM/r² 

                              F=GmM/r² 

Where , G = universal gravitational constant 

                       G = 6.67×10^-11 Nm²/kg² 

♦ Electromagnetic force::

• This force works between electric charge vie Electromagnetic field.
• This force is dominant in the interaction of atom
• This force is content of electric force & magnetic force.
• The entire Electromagnetic force on the charge particle is called Lorentz force

                              F = qE+qv×B

• The range of electromagnetic force is infinite.
• This interaction binds electrons to nuclei to form atom.

♦ weak nuclear interaction:: 

• This Force works between unstable nuclei.
• The decay in unstable subatomic particle happen due to weak interaction. Such as - Meson, w+ , w- , w⁰ etc.
• This force allow to turn proton into netron and vice-versa by beta decay.
• This interaction have short range.
• This interaction is responsible for radioactivity.

♦ Strong nuclear force::

• This force holds proton and neutron together.
• This force is responsible for nuclear interaction.
• The range of this force is 10^-15m
• This is strongest force/interaction in the universe.

♦Compression between fundamental interaction on the basis of range and strength::