Question

What are opaque bodies? Why are opaque bodies not called opaque mediums? Give four examples of the opaque bodies.

Answer 1

Hint: We know that the opaque substances do not allow the transmission of light. Any incident light gets reflected, absorbed, or scattered. Light rays can penetrate the substances to some depth. The light rays can be absorbed inside the medium. This process highly reduces the intensity of the incident light.

Complete answer:
As we know that the light rays can pass through these substances. The refractive index of transparent substances is nearly uniform. Most of the light, incident on a transparent object, transmits through it. Substances can be categorized into transparent, translucent, and opaque, based on the transmission of light through them. Transparent materials allow complete transmission of light whereas opaque materials do not transmit light at all. Translucent materials come in between the two former categories. These materials can partially transmit light. Light rays follow Snell’s law of refraction.
While passing through a transparent object, the amount of scattering is very less. Therefore, a clear image is seen on the other side of the substance. Window glasses are transparent in nature. Transparent materials are used for lenses, spherical mirrors, spectacles, and many more. Any object can be seen through a transparent material. One example of transparent material is pure glass. Some materials allow partial transmission of light.
These are called translucent substances. Opaque substances do not allow transmission. These properties are caused by absorption, reflection, and scattering of light. Light rays can penetrate opaque materials to some depth. Beyond that, the intensity of light gets attenuated. Due to scattering in translucent materials, light rays get randomly oriented. The emergent rays give rise to distorted and blurred images of objects, seen through a translucent material.

Note:
Remember that the opaque materials either reflect or absorb any incident light. As a result, light rays cannot pass through opaque materials. Wood, stone, etc. are opaque materials. Translucent materials allow partial transmission of light through them.