Since the magnetic field is determined by the velocities of all of the charges in and around the space in question (as opposed to the electric field, which is determined by the positions of the charges), the electromagnetic field will be equal to the electric field whenever all of the charge in the system is static.
(the magnetic field; is determined; by the velocities of all of the charges in and around the space in question) (the electric field; is determined; by the positions of the charges) (the electromagnetic field; will be; equal to the electric field) (all of the charge in the system; is; static)
the magnetic field the electric field the electromagnetic field all of the charge in the system
is determined is determined will be is
by the velocities of all of the charges in and around the space in question
by the positions of the charges
equal to the electric field
static