The moving object in magnetic fields generates a 'virtual" [...] electric fiied according to lorentz's law
E=Bxv
Since they are orogonal you get E=1.5 x 5 = 7.5V/m
Now you have a dielectri in a Eexternal=7.5V/m electric field.
The polarizatuion is P=Xe e0 E; er=(1+Xe)
but E is the field inside dielectric.
But you know (e0 Eext = e0 er Eint) since there are no free charges.
So: P=e0 (er - 1) Eext / er = 4.98 10^-11