Relation between the Image Position, Focal Length, and Object Position

The image position, focal length, and object position are related through the following equation

• Definitions
  • is the focal length measured in metres (m)
  • is the position of the object relative to the lens
  • is the position of the image relative to the lens (if it's negative it's on the same side of the lens as the incident ray).

Examples

Given a Thin Thin Concave Lens with a Focal Length of where is the Image Formed when an Object is Placed to the Left of the Lens

The lens creates a virtual image to the left of the lens.

Given a Thin Thin Concave Lens with a Focal Length of where is the Image Formed when an Object is Placed to the Left of the Lens

The lens creates a virtual image to the left of the lens.

Given a Thin Thin Convex Lens with a Focal Length of where is the Image Formed when an Object is Placed to the Left of the Lens

The lens creates a virtual image to the left of the lens.

Given a Thin Thin Convex Lens with a Focal Length of where is the Image Formed when an Object is Placed to the Left of the Lens

The lens creates a real image to the right of the lens.