Opaque materials are those that do not allow light to pass through. When light hits these materials, it gets blocked or absorbed. Examples of opaque materials include wood, stone, and metal. For instance, you cannot see through a wooden door or a metal box because they do not let light pass through. These materials are often used in construction or for creating objects that need to block light, like walls or containers.

This question related to Chapter 6 Science Curiosity Class 6th NCERT.
From the Chapter 6. Materials Around Us.
Give answer according to your understanding.