Question

State whether true or false.
The universal gravitational constant is independent of the intervening medium.
A. True
B. False

Answer 1

Hint: Define the universal law of gravitation. The gravitational constant is also known as the constant of gravity and is denoted by ‘G’. The value of the constant in SI units is $G=6.67\times {{10}^{-11}}{{m}^{3}}k{{g}^{-1}}{{s}^{-2}}$ . This is a universal constant with the same value everywhere.

Complete step by step answer: The gravitational force of attraction between two bodies of mass M and m at a distance R apart is given by,
$F=\dfrac{GMm}{{{R}^{2}}}$
Universal gravitational constant G is equal to the force of attraction between two bodies each of unit mass and placed at unit distance from each other. It is the proportionality constant in Newton's Law of Gravitation. it’s an empirical physical quantity that connects the gravitational force of attraction between two masses with the product of their masses and the inverse square of the distance between them.
Both electrostatic force and gravitational force follow the inverse square law but the former depends on the medium and the later doesn’t. Unlike electrostatic force, the strength of Gravitational force of attraction between two objects remains the same regardless of the material medium. This is due to the fact that the constant K in electrostatic force depends on the permittivity of the medium but the gravitational constant is independent of the permittivity of the medium. Thus, the value of G, $G=6.67\times {{10}^{-11}}{{m}^{3}}k{{g}^{-1}}{{s}^{-2}}$ will remain constant everywhere and it is independent of the intervening medium.
The correct answer is option A. True

Note: Students must note that the Newton’s Law of motion holds good for objects at very large distances but, it fails when the distance between two objects is of the order of intermolecular distances i.e. its less than ${{10}^{-9}}m$. At this limit strong forces or weak forces act on the body which are much stronger than the gravitational force.