TMal21 Spherical mirror object and image
A concave spherical mirror has radius of curvature of 20 cm. An object is placed 30 cm along the center line of the mirror.
What is the image distance and magnification?
Drawing the rays locates the image.
Draw a ray incident parallel to the center line and reflected through the focus.
Draw a ray incident through the focus and reflected parallel.
The intersection of these two lines defines the image.
Make the calculation to find the image distance.
The image distance is from the lens makers formula.
Remember: the focus is one-half the radius of curvature.
The image distance is 15 cm.
The magnification is - 15/30 = - 1/2.
The rays are drawn using rules 1 and 2.
Copyright © Robert M. Oman 2004