A linearly polarized electromagnetic wave given as E=Eoicos(kz-ωt) is incident normally on a perfectly reflecting infinite wall at z = a. Assuming that the material of the wall is optically inactive, the reflected wave will be given as
(a) Er= -Eoi cos(kz-ωt).
(b) Er= Eoi cos(kz+ωt).
(c) Er= -Eoi cos(kz+ωt).
(d) Er= Eoi sin(kz-ωt).
