Concave Mirror Blocking Simulation
Interactive demonstration of image formation when part of a concave mirror is blocked
Blocking Scenarios
Example
Question:
Suppose that the lower half of the concave mirror’s reflecting surface in Fig. 9.6 is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?
Solution:
At first, one might think the image would show only half of the object. However, applying the laws of reflection to all points on the remaining (uncovered) part of the mirror, the image will be of the whole object. As the reflecting surface area is reduced, the intensity of the image will be low (in this case, half).
Interactive Controls
Display Options
Physics Explanation
Common Misconception
Many people think that blocking half the mirror will show only half the object. This is incorrect!
Correct Physics
Each point on the object sends rays to ALL parts of the mirror surface. Even when part is blocked, the complete image still forms.
Brightness Reduction
Blocking reduces the amount of light collected by the mirror, making the image dimmer but complete. The brightness is approximately proportional to the unblocked area.
Real-World Applications
This principle applies to car mirrors with obstructions, telescopes with secondary mirrors, and camera aperture effects.



