What is the lens formula?

The lens formula is a mathematical representation that relates the focal length of a lens to the distances of the object and the image from the optical center of the lens. It is crucial in optics and is used to determine the properties of an image formed by a lens.

The Lens Formula

The lens formula is expressed as:

1/v + 1/u = 1/f

• v represents the distance of the image from the lens' optical center.
• u (or sometimes denoted as o) is the distance of the object from the lens' optical center.
• f is the focal length of the lens.

Explanation of the Lens Formula

The lens formula applies to both convex and concave lenses. It helps in calculating the position and nature of the image formed by the lens. The formula assumes that all measurements are taken along the principal axis of the lens and adhere to the sign convention:

• Distances measured in the direction of the incident light are positive.
• Distances measured against the direction of the incident light are negative.

Applications of the Lens Formula

The lens formula is extensively used in physics to solve problems related to image formation. It finds applications in:

• Calculating the magnification of an image.
• Determining whether an image is real or virtual.
• Finding the focal length of an unknown lens through experiments.

Understanding the lens formula is essential for students and professionals working in fields such as physics, photography, and optical engineering.