Ray Diagrams for Mirrors

Concave Mirror: ObjectBeyondCenter of Curvature

  1. Measure from the mirror to center of curvature. Label the focal point which is half of the distance between the mirror and center of curvature.
  2. Draw a ray from the top of the object (arrow) parallel to the principal axis to the mirror, and reflect back through the focal point. Don’t forget to put arrows on the incident and reflected rays.
  3. Draw another ray from the top of the object through the focal point to the mirror, and reflect back parallel to the principal axis.
  4. Where the two rays meet, the top of the image is formed. These are real light rays that really converge to form the image. Since the bottom of the object lies on the principal axis, the bottom of the image will also be on the principal axis. Sketch the image.
  5. Measure and record the following in the data table below: focal length, object distance, image distance, object height, and image height.

Focal length
(f) / Object distance(do) / Image distance(di) / Type of image / Object height
(ho) / Image height
(hi) / Magnification
(M) / Orientation
  1. Calculate the magnification of the image using the equation and record in the table.

Concave Mirror: Object Between Focal Point and Center of Curvature

  1. Repeat steps 1 through 4 from above procedure. This time the bottom does not lie on the principal axis
  2. Now, with a pen or pencil of another color follow the same steps to locate the bottom of the image. Sketch the image.
  3. Measure and record the following in the data table below: focal length, object distance, image distance, object height, and image height.

Focal length
(f) / Object distance (do) / Image distance (di) / Type of image / Object height
(ho) / Image height
(hi) / Magnification
(M) / Orientation
  1. Calculate the magnification of the image using the equation and record in the table

Concave Mirror: Object at Center of Curvature

  1. Repeat steps 1 through 5 in the directions for the first diagram above

Focal length
(f) / Object distance (do) / Image distance (di) / Type of image / Object height
(ho) / Image height
(hi) / Magnification
(M) / Orientation
  1. Calculate the magnification of the image using the equation and record in the table

Concave Mirror: Object Inside the Focal Point

  1. Repeat steps 1 and 2 from first set of directions.
  2. Draw another ray from the top of the object toward the mirror as if it were coming from the focal point to the mirror, and reflect back parallel to the principal axis.
  3. The two rays will never meet so NOreal image will be formed. Extend the reflected rays behind the mirror using dashed lines for virtual rays until they intersect. This is where the image will be formed. Sketch the image.
  4. Measure and record the following in the data table below: focal length, object distance, image distance, object height, and image height.

Focal length
(f) / Object distance (do) / Image distance (di) / Type of image / Object height
(ho) / Image height
(hi) / Magnification
(M) / Orientation
  1. Calculate the magnification of the image using the equation and record in the table

Convex Mirror:

  1. Measure from the mirror to center of curvature. Label the focal point which is half of the distance between the mirror and center of curvature.
  2. Draw a ray from the top of the object (arrow) parallel to the principal axis to the mirror, and reflect back as if the reflected ray came from the focal point. Lines behind the mirror are virtual rays and should be dashed. Don’t forget to put arrows on the incident and reflected rays.
  3. Draw another ray from the top of the object as if it would pass through the focal point to the mirror’s surface. Then reflect back parallel to the principal axis.
  4. Extend the reflected ray (using dashed lines) behind the mirror until the two dashed lines intersect, that is where the image is formed.
  5. Now, with a pen or pencil of another color follow the same steps to locate the bottom of the image. Sketch the image.
  6. Measure and record the following in the data table below: focal length, object distance, image distance, object height, and image height.

Focal length
(f) / Object distance (do) / Image distance (di) / Type of image / Object height
(ho) / Image height
(hi) / Magnification
(M) / Orientation
  1. Calculate the magnification of the image using the equation and record in the table