Light
Reflection and transparency
Concave and convex reflection
Refraction of light: Introduction
Refraction of light: Total internal reflection
Concave and convex reflection
What does a concave mirror look like?
What are you doing? Check this out. Very mature. If you turn it around, the image turns upside down. Let me see. Why? A shiny spoon is like a mirror - only curved. Since the surface is completely smooth, it gives a mirror image - a specular reflection. But since it's curved, the rays of light are reflected in different directions depending on where they hit the spoon. This side that bulges out is called the convex side. The rays of light bounce off the spoon, and at the exact point that a ray hits the surface, its angle of incidence is the same as the angle of reflection.
But since the spoon is curved, the normal is different at different points. A convex mirror gathers the rays of light together from a larger area than an ordinary flat mirror. Look at the angles of reflection close to the edges. They are wider than those on a flat mirror. Philip sees a wide-angle image.
A convex mirror makes what you see smaller and more so as you look closer to the edges. Convex mirrors are sometimes used to see around corners in traffic or in stores to detect shoplifters. Turn the spoon around. This side which curves inwards is called concave. It's hollow like a cave. A concave mirror gathers the rays of light hitting it.
That's why if you are close to a concave mirror, you see an enlargement. A concave mirror can be useful in the bathroom when you're putting on make-up or shaving. If you back away from a concave mirror, you reach the focal point. At this point, the image gets all fuzzy. All the parallel incident rays of light are collected at the focal point.
If you keep moving backwards, the image in a concave mirror turns upside down. The rays of light cross at the focal point and come out on the opposite side. Upside down. Right side up. Upside down.
Right side up.