Question

Induced polarisation in non-polar molecules occurs because:

Options

• The permanent dipoles rotate and align with the field

• Free charge carriers migrate to the surface of the material

• The external field slightly separates the positive and negative charge centres

• Thermal motion randomly orients the dipoles

Answer 1

Non-polar molecules have no permanent dipole, so polarisation occurs by induction: the external field slightly separates the positive and negative charge centres in opposite directions, creating an induced dipole moment.