Mirror Formula and Magnification
The Mirror formula relates the object distance (u), image distance (v), and focal length (f) of a spherical mirror.
1/f = 1/u + 1/v
In the Mirror formula
- u is the distance from the object to the mirror (positive when the object is in front of the mirror, negative when behind),
- v is the distance from the image to the mirror (positive the when the image is in front of the mirror, negative when behind).
- f is the Focal length of the mirror (positive for concave mirrors, negative for convex mirrors).
These parameters u, v and f in mirror formula uses sign convention in mirrors and take sign accordingly.
Magnification
The ratio of the height of the object to the height of the image is called linear magnification. (m) which describes the relative size of the image compared to the object. It can be calculated using two different formulations,
Ratio of image height to object height
m = hi/ho
In this formula
- m is the Magnification (positive for enlarged images, negative for diminished images, and 1 for the same size),
- hi is the Height of the image
- ho is the Height of the object.
Ratio of image distance to object distance
m = – v/u
This formula relates magnification directly to the object and image distances through the mirror formula. The negative sign indicates that the image formed by a spherical mirror is typically inverted
- If |m| < 1 then the size of the image is smaller than the object. The negative value of linear magnification shows that the image is real and inverted.
- If |m| > 1 then the size of the image is greater than the object.
Ray Optics – Definition, Formula, Applications
Ray Optics is the study of properties of light and optical instruments by assuming that light travels in a straight line. It is also known as geometrical optics, which deals with the geometry of light. Light always travels in a straight line, and the direction in which the light rays propagate is called the ray of light. It studies the principles and laws governing the propagation of light, particularly in the absence of wave effects such as interference and diffraction.
In this article, we will learn about ray optics, reflection, refraction, concave and convex mirrors, lenses, and formulas related to them.