試題詳解

1. About electromagnetic radiation, which description is incorrect?
(A) It includes magnetic and electric fields.
(B) Gamma ray, X-ray, visible light, electron beam, microwave, and radio waves all are electromagnetic radiations.
(C) Electromagnetic radiation is a kind of energy.
(D) The propagation directions of electric and magnetic fields in the electromagnetic radiation are in 90°.
(E) The velocity of visible light from an illuminator in the vacuum environment is always the same in the two conditions when the illuminator is moving toward and away from the observer.