Convex vs Concave Lens

Lenses in Physics (Optics)

A lens is a transparent material (usually glass or plastic) with at least one curved surface that refracts (bends) light rays to form an image.

Lenses belong to the branch of Physics, specifically Optics, under the topic Refraction of Light.

1. Convex Lens (Converging Lens)

Shape:

1. Thicker at the center / 2. Thinner at the edges

Ray Behavior:

Bends (refracts) parallel rays of light inward, so they converge at a point (called the focus)

Image Formation:

• Depends on object distance / Can form real & inverted images (when object is beyond focal length) / Can form virtual, erect & magnified image (when object is within focal length)

Uses:

Magnifying glass / Microscopes & telescopes / Cameras / Corrects farsightedness (Hypermetropia)

2. Concave Lens (Diverging Lens)

Shape:

• Thinner at the center / Thicker at the edges

Ray Behavior:

• Bends parallel rays of light outward / Appears to diverge from a point called the focus

Image Formation:

• Always forms a virtual, erect, and smaller image, no matter the object distance

Uses:

• Eyeglasses for nearsightedness (Myopia) / Peepholes in doors / Laser beam expanders