When light strikes an object through which it cannot pass, this is formed:

• A. Reflection
• B. Refraction
• C. Absorption
• D. Shadow

Answer: (D)

Light travels in straight lines, so when an opaque object blocks the path of light, no light reaches the surface behind it. That results in a shadow—a dark area whose shape matches the object as seen from the light source. A shadow forms specifically because the light cannot pass through the object, not because light is bouncing off (that would be reflection) or bending as it passes through a different material (that would be refraction) or being absorbed inside the object (which happens, but doesn’t create the visible dark area behind it). If you shine a light on your hand, you’ll see a shadow on the wall where the light was blocked.