Which objects are considered opaque?

• A. Textbook
• B. Light bulb
• C. Track shoes
• D. Basketball

Answer: (A)

The correct choice identifies a textbook as an opaque object. Opaque materials do not allow light to pass through them; instead, they absorb or reflect all the light that strikes their surface. A textbook is typically made from materials like paper and cardboard that effectively block light, preventing any visibility of objects on the other side.

In contrast, the other objects listed may have different properties. A light bulb can allow some light to be emitted through it, especially if it is a transparent or translucent bulb. Track shoes are often made with materials that can be either transparent or opaque, but they are typically not classified primarily for their light-blocking properties. A basketball, while not see-through, may not completely block light as the surface can appear somewhat translucent when light is shone on it, depending on the material used for its construction. Thus, a textbook is a definitive example of an opaque object.