The Basic Forces in Nature

Gravitational force

• It is the force of attraction between any two bodies in the universe.

• The gravitational force is inversely proportional to the square of the distance between the two bodies and directly proportional to the product of the masses of two bodies.

• Gravitational force is small when light bodies are considered and is considerable when massive bodies are taken into account.

Electrostatic force

• It's the force between two charges.

• It's stronger than gravitational force.

• It also follows inverse square law and is proportional to product of the point charges.

Magnetic force

• It can be either attractive or repulsive.

• It can be the force between two magnets or force on a magnet placed in a magnetic field.

Electromagnetic force

• An electric charge moving in a magnetic field experiences a force.

• This is called electromagnetic force. It is a combination of electricity and magnetism.

Nuclear force

• This is a strong force with a short range.

• It is non-central, i.e., it isn't directed along the line joining the centres of the interacting particles.

• This force acts within the nucleus.

Weak force

• This kind of interaction is not well understood as yet.

• Its range is shorter than the nuclear force.

• It is important only for certain nuclear processes like radioactive beta decay.

10² : 1 : 10^-12 : 10^-36

Comparison of electrostatic and gravitational forces

Points of similarity

• They are central forces.

• They obey inverse square law.

• They are conservative forces.

• They operate even in vacuum.

Points of dissimilarity

• Gravitational forces are attractive while electrostatic forces may be attractive or repulsive.

• Gravitational constant of proportionality doesn't depend on the medium while electrical constant depends on the medium.

• Electrostatic forces are extremely large as compared to gravitational forces.