Experiment 7: Concave and Convex Mirrors

In this experiment we analyzed the differences between concave and convex mirrors. We will begin to analyze them by looking at how images appear when looking through the mirrors. We looked at convex mirrors first. Convex mirrors are shaped as if they were pushed outward from a thin straight glass plate.

In the convex mirror the image appears smaller than it's actual size. The image in the mirror still appears upright after looking in the mirror. The image in the mirror appears to also be further away than when the object distance from the mirror. When the object is moved closer to the mirror it appears closer to its true size and is slightly curved. 

The ray diagram agrees with the observations that we had. The images look smaller the further away the object is. The image height is much smaller than the original object height in the ray diagram. The top ray bounces off at an angle and the reflection goes through the focal point of the mirror. The second ray goes through the center and reflects back in the same direction it came in at. The third ray goes down and bounces off parallel to the optic axis. It also reflects in the mirror parallel. These three rays meet and create an image that is smaller than the actual object. These are the measured values on the ray diagram.
h_0 = 2.9 cm + 0.1 cm. h_i  = 0.7 cm + 0.1 cm d_0 = 5.9 cm + 0.1cm d_i = 1.9 cm + 0.1 cm.
The M calculated would be 0.241 + 0.2.

Convex Mirror Ray Diagram

After analyzing convex mirrors, we turned our attention to concave mirrors. Concave mirrors are curved inwards from the shape of a glass plate.

The image in a concave mirror behaves differently than the convex mirror. The image appears larger than the original. It is also inverted if you are far away but the picture becomes upright when you get close to the mirror. When you are relatively close to the mirror about under 1 meter, The object appears larger than it actually is. When you are far from the mirror, the object is inverted but looks like its true size. 

A ray diagram can also describe the phenomena of the concave mirror. 

Concave Mirror Ray Diagram

This ray diagram also agrees with the observations. In this diagram the top ray bounces off the mirror and goes through the focal point. The second ray goes through the focal point and reflects back parallel to the optical axis. The third ray goes through the radius of curvature and goes straight through. The place where the three rays meet is where the image is created. These are the measured values on this ray diagram.
h_0 = 3.1 cm + 0.1 cm h_i = 0.8 cm + 0.1 cm d_0 = 11.6 cm + 0.1 cm d_i = 2.5 cm + 0.1 cm.
The calculated M would be 0.258 + 0.2

Conclusion

Convex mirrors and concave mirrors behave differently. When objects are inside the focal length of a concave mirror, they are large and inverted. When objects are far from the concave mirror, outside of the focal length, they appear inverted and smaller. Convex mirrors produce real images but they are not inverted. The also produce virtual images inside of the mirror.