Image formed by the Convex Lens

There are six different cases for image formation by a convex lens, which are discussed as:

When an Object is at Infinity

When object AB (shown in the figure below) is placed at infinity that is behind the 2F₁ of the convex mirror, the image formed after the refraction will on focus F₂ which is on the opposite side of the convex lens. The size of the image is smaller than the object and the image will be real and inverted(i.e upside down and downside up).    

• The image formed at – Focus (F₂)
• The nature of the image formed – Real and inverted
• The size of the image formed – Diminished (smaller)

When an Object is placed Behind the Centre of Curvature (C₁)

When the object is placed behind the center of curvature (C₁) or behind the Focus (2F₁) of the convex lens, the image formed after the refraction will be between the foci of another side of the lens (i.e. F₂ and 2F₂). The size of the image is smaller than the object. The nature of the image will be real (can be seen on the screen) and inverted( upside down).

• The image formed at – Between 2F₂ and F₂.
• The nature of the image formed – Real and inverted
• The size of the image formed – Diminished (smaller)

When the Object is placed at the Center of Curvature (C₁ or 2F₁)

When an object is placed at the center of curvature (C₁) or focus (2F₁) of the convex lens, the image formed after the refraction will be on the center of curvature (C₂) or focus (2F₂) on the other side of the lens. The size of the image is the same as the size of the object. The nature of the image is real and inverted.

• The image formed at – C₂ or 2F₂.
• The nature of the image formed – Real and inverted
• The size of the image formed – Equal to the object size.

When the Object is placed between 2F₁ and F₁

When an object is placed between the center of curvature and the focus (F₁) of the convex lens, the image formed after reflection will be behind the center of curvature (C₂). The size of the image will be greater than the object. The nature of the image will be real and inverted.

• The image formed – Behind the center of curvature (C₂)
• The nature of the image formed – Real and inverted
• The size of the image formed – Enlarged

When the Object is placed at Focus (F₁)

When an object is placed at focus (F₁) of a convex lens. The image formed after reflection will be at infinity (opposite side of the lens). The size of the object will be much larger than the object. The nature of the image will be real and inverted.

• The image formed at – Infinity (opposite side of the object)
• The nature of the image formed – Real and inverted
• The size of the image formed – Enlarged

When the Object is placed between Pole and Focus (O and F₁)

When the object is placed between the focus (F₁) and the optic center (O) of the convex lens. The image is formed at the same side of the object behind the center of curvature (C) or focus (F₁) of the lens. The size of the image will be larger than the object. The nature of the image will be Virtual Erect.

• The image formed – At the same side of the object behind 2F₂.
• The nature of the image formed – Virtual and Erect.
• The size of the image formed – Enlarged

In optics, a ray is a geometrical representation of the light that is idealized by choosing a curve that is perpendicular to the wave fronts of actual light and points in the energy flow direction. Rays are used to represent the propagation of light through an optical system by separating the real light field into discrete rays that can be computationally carried through the system using ray-tracing techniques. This makes it possible to investigate or simulate even the most complex optical systems mathematically. Ray tracing is based on approximate solutions to Maxwell’s equations that hold true as long as light waves flow through and around objects with dimensions significantly greater than the wavelength of the light. Diffraction, for example, necessitates the study of wave optics, which is not addressed by ray or geometrical optics. Adding phase to the ray model can be used to describe wave phenomena such as interference in some instances.