Final answer:
Answer (a) correctly describes diffuse reflection and is not related to the Doppler effect or other phenomena like diffraction. Diffuse reflection occurs when light is scattered in many directions upon hitting a rough surface, unlike the uniform direction seen in specular reflection.
Step-by-step explanation:
Diffuse reflection is a type of reflection where light rays incident on a rough surface are scattered in various directions. This is different from specular reflection, where light rays are reflected in a single direction from a smooth surface. In diffuse reflection, the reflected beam is scattered, as illustrated by how a sheet of paper (a rough surface) reflects light, allowing it to be seen from many angles.
The correct answer to which descriptions apply to diffuse reflection is (a) The reflected beam is scattered in various directions. This is because diffuse reflection does not alter the wave's frequency, amplify the beam, or necessarily mean there is no reflection at an interface. The reflection of a wave is better defined as the change in direction of the wave upon hitting a barrier, as clarified by the physics concept of scattering and wave interaction with materials. The Doppler effect involves a change in observed frequency due to relative motion and is not directly related to reflection. Moreover, the concepts of the reflection spectrum being selective and light diffraction are different phenomena not directly answering the question about diffuse reflection.