(N/A) London dispersion forces are weak intermolecular forces that arise due to the motion of electrons in atoms and nonpolar molecules.
$1$. Atoms and nonpolar molecules are electrically symmetrical and have no permanent dipole moment because their electronic charge cloud is symmetrically distributed.
$2$. However,a dipole may develop momentarily even in such atoms and molecules. Suppose we have two atoms '$A$' and '$B$' in close proximity.
$3$. It may happen that momentarily,the electronic charge distribution in one of the atoms,say '$A$',becomes unsymmetrical,meaning the charge cloud is more concentrated on one side than the other. This creates an 'instantaneous dipole'.
$4$. This instantaneous dipole in atom '$A$' creates an electric field that distorts the electron cloud of the neighboring atom '$B$',inducing a dipole in it. This is called an 'induced dipole'.
$5$. The attraction between the instantaneous dipole and the induced dipole is known as the London dispersion force. These forces are always attractive and their magnitude depends on the polarizability of the atoms or molecules.