convex lenses are used in the human eye to help focus light onto the retina, allowing us to see clearly. The natural lens in the human eye is flexible and can change its shape, allowing it to adjust the focal length and focus on objects at different distances. This process is called accommodation and is essential for clear vision.

Accommodation in the eye lens is the process of adjusting its shape to focus on objects at different distances. This adjustment is controlled by the ciliary muscles. When focusing on nearby objects, these muscles contract, thickening the lens. For distant objects, the muscles relax, flattening the lens, ensuring clear vision at varying distances.

A torch emits a divergent light beam, where light rays spread out as they move away from the source. This spreading allows the flashlight to illuminate a wider area, making it useful for various tasks. Divergent beams are common in flashlights, ensuring efficient coverage and visibility in the dark.

A concave mirror is used in a solar cooker. Specifically, a concave mirror focuses sunlight onto a small area, increasing the intensity of the sunlight and generating heat. This concentrated sunlight is then used for cooking in solar cookers, harnessing solar energy for practical applications.

The image formed by a plane mirror (also known as a flat mirror) is called a "virtual image." A virtual image is an image that is not real but appears as if it were. It is formed behind the mirror, and it appears to be the same size as the object being reflected. This image is upright (erect) and reversed from left to right, but it is not a tangible object; it exists as a result of the way light rays reflect off the mirror's surface.

If the image formed in a mirror is always erect (upright) and equal in size to the object, the mirror is a flat mirror (plane mirror). Flat mirrors reflect light without distorting the image, producing an erect image that is the same size as the object and reversed from left to right.

Flat Mirror (or Plane Mirror): Reflects light without distorting the image. The image formed is erect (upright) and of the same size as the object, but reversed from left to right.

Convex Mirror: Also produces an erect image. The image formed is virtual (cannot be projected onto a screen), smaller than the actual object, and upright.

Both flat and convex mirrors can create upright (erect) images of real objects.