Dipole forces Question

How to identify permanent vs induced dipole forces? Thanks!

Hi! Permanent dipoles are in polar molecules when there is a NET direction of electron density eg: HCl - there’s a permanent dipole where Cl is slightly negative and H is slightly positive because Cl is electronegative. There has to be a significant difference in electronegativity which is why Cl2 is NON polar - doesn’t have permanent dipoles.
Induced dipole/ London forces is basically present between every molecule especially between molecules that aren’t polar. Between two NaCl molecules. It’s a very weak bond and it only happens instantaneously where the electrons move towards a positive atom.
Hope this helps! It’s what I used to understand. To get into more detail you can use YouTube!