An object in which no light rays can pass through is called—

The correct answer is opaque.

Objects are classified based on how much light can pass through them:

1. Opaque objects: These objects do not allow any light to pass through them. When light hits an opaque object, it is either reflected or absorbed, resulting in a shadow behind the object. Examples include wood, metals, and stone.
2. Translucent objects: These objects allow light to pass through partially, but scatter it so that objects on the other side cannot be seen clearly. Examples include frosted glass and butter paper.
3. Transparent objects: These objects allow almost all light to pass straight through them, making objects on the other side clearly visible. Examples include clear glass and pure water.
4. Convex: This refers to a curved shape or lens, not a category of light transmission.

Since the question asks for an object through which no light rays can pass, the correct term is opaque.