when a dielectric is placed in external electric field then the polarised electric field is not equal to the external electric field but in case of conductor it is equal why

It is so bcoz in case of conductor the value of dielectric constant is always taken as ''1'' i.e K = 1

but when a conductor is placed in an electric field there k is not equals to 1 and therefore when a dielectric is placed in external electric field then the polarised electric field is not equal to the external electric field but in case of conductor it is equal

plz approve