Question 1

What is the thin lens equation?

Accepted Answer

The thin lens equation is 1/f = 1/do + 1/di, where f is the focal length, do is the object distance, and di is the image distance. It applies to both converging (convex) and diverging (concave) lenses. Converging lenses have positive focal lengths; diverging lenses have negative focal lengths.

Question 2

How do I determine if an image is real or virtual?

Accepted Answer

If the image distance di is positive, the image is real and forms on the opposite side of the lens from the object. If di is negative, the image is virtual and appears on the same side as the object. Real images are inverted; virtual images produced by a single lens are upright.

Question 3

What is magnification in optics?

Accepted Answer

Magnification m = -di/do. If |m| > 1, the image is enlarged; if |m| < 1, it is reduced. A negative magnification means the image is inverted relative to the object. A positive magnification means the image is upright.

Thin Lens Equation Calculator