How do insulators behave in an external electric field?

In an external electric field, insulators do not allow electric charges to move freely through them.

Insulators, also known as non-conductors, are materials that do not allow the free movement of electric charges. When an external electric field is applied, the charges within the insulator do not move or drift towards the opposite charge. This is due to the strong bonds between the atoms in the insulator that hold the electrons tightly, preventing them from moving freely.

The behaviour of insulators in an external electric field can be further understood by looking at the atomic structure of these materials. The electrons in an insulator are tightly bound to their atoms and cannot move to other atoms easily. This is in contrast to conductors, where some electrons are loosely bound and can move freely. When an electric field is applied to an insulator, the electrons remain bound to their atoms and do not drift towards the positive end of the field.

However, it's important to note that while the charges in an insulator do not move, they do experience a force due to the external electric field. This force can cause a slight shift in the position of the charges, leading to a phenomenon known as polarisation. Polarisation is the slight displacement of charges within the insulator, causing one side of the insulator to become slightly more positive and the other side to become slightly more negative.

In summary, insulators do not allow the free movement of charges when an external electric field is applied. The charges within the insulator are tightly bound to their atoms, preventing them from drifting towards the opposite charge. However, the charges do experience a force due to the electric field, leading to a slight displacement of charges known as polarisation.