Image distance is the distance between the image formed by a lens and the lens itself. It is usually denoted by $d_i$ and can be positive or negative depending on the type of image formed.
congrats on reading the definition of Image distance. now let's actually learn it.
The sign of the image distance ($d_i$) indicates whether the image is real (positive $d_i$) or virtual (negative $d_i$).
Image distance can be calculated using the lens equation: $\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$, where $f$ is the focal length and $d_o$ is the object distance.
In a converging lens, a real image forms on the opposite side of the object, making $d_i$ positive.
In a diverging lens, a virtual image forms on the same side as the object, making $d_i$ negative.
The magnification of an image can be found using $\text{Magnification} = -\frac{d_i}{d_o}$.
Review Questions
How do you determine if an image is real or virtual based on its image distance?
What does a positive value for image distance signify in terms of image formation?
How would you use the lens equation to solve for an unknown image distance?
Related terms
Object Distance: The distance between an object and a lens, usually denoted by $d_o$. It influences where and how an image will form.
$\text{Magnification} = \frac{\text{Image Height}}{\text{Object Height}} = -\frac{d_i}{d_o}$. It describes how much larger or smaller an image is compared to its object.