Optics

Front

Concave Mirror Noun

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[kon-kayv meer-er]

Back

Concave Mirror

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A mirror with a surface that curves inward, capable of forming both real and virtual images of various sizes.

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Example: This diagram shows how a concave mirror reflects light rays from an object. The rays converge to form a real, inverted image.

Front

Convex Mirror Noun

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[kon-veks meer-er]

Back

Convex Mirror

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A mirror with a surface that curves outward, which consistently forms a reduced, upright, and virtual image of an object.

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Example: This diagram shows how light rays from an object reflect off a convex mirror's curved surface, appearing to come from a smaller, upright image behind it.

Front

Real Image Noun

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[reel im-ij]

Back

Real Image

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An image formed by the actual convergence of light rays at a specific location, which can be projected onto a screen.

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Example: This ray diagram shows light rays from an object reflecting off a concave mirror and converging at a single point to form an inverted, real image.

Front

Virtual Image Noun

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[vur-choo-ul im-ij]

Back

Virtual Image

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An image formed where light rays appear to diverge from, but do not actually converge, and cannot be projected.

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Example: Light rays from an object reflect off a plane mirror. The brain traces these rays back to a point behind the mirror where the virtual image appears.

Front

Focal Point Noun

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[foh-kul point]

Back

Focal Point

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The specific point where parallel light rays converge after reflection from a concave mirror or refraction through a convex lens.

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Example: Light rays originating from the focal point of a convex lens travel in parallel lines after passing through the lens.

Front

Convex Lens Noun

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[kon-veks lenz]

Back

Convex Lens

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A lens that is thicker at its center than at its edges, causing parallel light rays to converge to a focus.

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Example: A convex lens, which is thicker in the middle, bends parallel light rays inward to meet at a single spot called the focal point.

Front

Reflection Noun

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[ri-flek-shun]

Back

Reflection

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The bouncing back of a wave, such as light or sound, after it strikes a surface that it cannot pass through.

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Example: A beam of light from a source (incident ray) hits a mirror and bounces off (reflected ray), with the angle of incidence equaling the angle of reflection.

Front

Refraction Noun

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[ri-frak-shun]

Back

Refraction

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The bending of a wave as it passes from one medium to another, resulting from a change in its speed.

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Example: This image shows how a ray of light bends (refracts) when it passes from a less dense medium (air) to a denser medium (water).

Front

Total Internal Reflection Noun

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[toh-tl in-tur-nl ri-flek-shun]

Back

Total Internal Reflection

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The complete reflection of a light ray back into its original medium when it strikes a boundary at a steep angle.

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Example: This diagram shows how a light ray travels through a curved optic fiber by repeatedly bouncing off the inner walls, demonstrating total internal reflection.

Front

Reflecting Telescope Noun

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[ri-flek-ting tel-uh-skohp]

Back

Reflecting Telescope

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An optical instrument that uses a curved mirror and lenses to gather and focus light from distant objects to form an image.

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Example: A reflecting telescope uses a large curved mirror to gather light and a smaller flat mirror to reflect the light to an eyepiece for viewing.