Mirrors in General
Java Applets for Physics "Physlets®" Courtesy
- Add a plane mirror to the work area and see how to move it back and forth.
- Add a "Parallel beam" source to the work area and see how to move it around
and change the direction of the beam.
- Click and drag an empty part of the workspace and note how the pointer
measures an angle from the right side horizontal.
- Use the angle measure tool to determine the incident (from the source)
and reflected angles of rays with the source in several different positions.
How is the incident angle related to the reflected angle?
- Clear the workspace and add a plane mirror and a point source.
- Measure the incident and reflected angles of several rays.
Is this consistent with the result of item #4?
- Clear the workspace and add a plane mirror and an object.
- Move the mirror and the object and observe the characteristics of the image.
Is it possible to produce an image on the same side of the mirror as the
How are the sizes and positions of object and image related to one another?
- Clear the workspace and add a concave mirror and a point source.
- Move the mirror, the source or both so that it is easy to find several
rays that reflect from the mirror
directly along the original path. Only one or two rays will do this at
Measure the distance between the mirror and the point on the axis where
these rays cross.
What is the significance of this point?
- Clear the workspace and add a concave mirror and a parallel beam.
- Move the parallel beam up and down while leaving the beam horizontal.
Where do all of the rays converge?
What is this point called? How far from the mirror is this point?
How does this position compare to the answer in step #10?
- Clear the workspace and add a concave mirror and an object.
- Move the object and/or the mirror and observe the characteristics of the
What kind of images are possible and under what circumstances?
How is the size of the image related to the size and position of the object?
How is the position of the image related to the position of the object?
What is the significance of each of the points determined in steps 10 and 12?
- Clear the workspace and experiment with the convex mirror.
What can be said about the images formed by convex mirrors?
Wednesday, March 8, 2006