Which term means the lighter part of a shadow where light is partially blocked?

Which term means the lighter part of a shadow where light is partially blocked?

• A. Doldrums
• B. Umbra
• C. Penumbra
• D. Adhesion

Answer: (C)

When light is blocked by an object, the resulting shadow has two zones. The darkest region is where all the light is blocked, called the umbra. The lighter, partially blocked portion surrounding it is the penumbra. The penumbra is why you see a shadow that isn’t solely dark at the edges—some light leaks around the edges of the object. This term also comes up in eclipses: the penumbra is where a partial eclipse is visible, while the umbra is where a total eclipse can be seen. The other terms aren’t about shadows—doldrums refer to calm wind belts near the equator, and adhesion is a force that causes surfaces to stick together.

When light is blocked by an object, the resulting shadow has two zones. The darkest region is where all the light is blocked, called the umbra. The lighter, partially blocked portion surrounding it is the penumbra. The penumbra is why you see a shadow that isn’t solely dark at the edges—some light leaks around the edges of the object. This term also comes up in eclipses: the penumbra is where a partial eclipse is visible, while the umbra is where a total eclipse can be seen. The other terms aren’t about shadows—doldrums refer to calm wind belts near the equator, and adhesion is a force that causes surfaces to stick together.