They are called <span>Frequency-modulated</span>
I definitely agree with choise that you consider to be as a correct one. I am pretty sure that prganism is correct because this is a unit which ebrases all the mentioned points. And in simple words, the rest of options represent collective objects but you have to answer with sole one. Hope you find it helpful.
Answer:In geometric optics, the angle of incidence is the angle between a ray incident on a surface and the line perpendicular to the surface at the point of incidence, called the normal. The ray can be formed by any wave: optical, acoustic, microwave, X-ray and so on. In the figure below, the line representing a ray makes an angle θ with the normal. The angle of incidence at which light is first totally internally reflected is known as the critical angle. The angle of reflection and angle of refraction are other angles related to beams.
Explanation:tik tok: Uh.amy07
