Reflection and Refraction

Front

Luminous Adjective

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[loo-mi-nuhs]

Back

Luminous

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An object that produces and gives out its own light, serving as a primary source of illumination.

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Example: Luminous objects, such as the sun and a lightbulb, are sources that produce and emit their own light, making them visible in the dark.

Front

Non-luminous Adjective

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[non-loo-mi-nuhs]

Back

Non-luminous

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An object that does not produce its own light and is seen by reflecting light from another source.

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Example: A non-luminous object is visible because it reflects light; it can also absorb light (appearing dark) or transmit light (appearing transparent).

Front

Transparent Adjective

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[trans-pair-uhnt]

Back

Transparent

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A material that allows all light to pass through it, so objects behind can be seen clearly.

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Example: This diagram shows that a transparent material allows light rays from a flashlight to pass straight through it without being scattered or blocked.

Front

Translucent Adjective

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[trans-loo-suhnt]

Back

Translucent

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A material that allows some light to pass through it, but scatters the light as it passes.

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Example: A translucent material lets some light pass through but scatters it, making objects behind it look blurry and unclear.

Front

Opaque Adjective

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[oh-payk]

Back

Opaque

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A material that does not allow any light to pass through it, instead absorbing or reflecting it.

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Example: An opaque object blocks light from passing through it, which is why it casts a shadow when a light source shines on it.

Front

Reflection Noun

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[ri-flek-shuhn]

Back

Reflection

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The bouncing of light when it strikes a surface and is redirected away from that surface.

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Example: A light ray from a source (incident ray) hits a mirror and bounces off (reflected ray). The angle of incidence equals the angle of reflection.

Front

Absorption Noun

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[ab-sorp-shuhn]

Back

Absorption

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The process where light energy is taken in by an object rather than being reflected or transmitted.

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Example: Light rays from a source strike a black surface, which absorbs the light energy and transforms it into heat energy.

Front

Incident Ray Noun

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[in-si-duhnt ray]

Back

Incident Ray

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The incoming ray of light that strikes a surface before any interaction like reflection or refraction occurs.

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Example: This diagram shows an incident ray as the beam of light that travels through the air and strikes the boundary of the water before bending.

Front

Reflected Ray Noun

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[ri-flek-tid ray]

Back

Reflected Ray

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The outgoing ray of light that has bounced off a surface after the process of reflection.

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Example: This diagram shows a light ray (incident ray) hitting a surface and bouncing off as a reflected ray, following the law of reflection.

Front

Normal Noun

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[nor-muhl]

Back

Normal

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An imaginary line drawn at a right angle to a surface at the point where a light ray hits.

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Example: The 'Normal' is an imaginary line drawn perpendicular (at a 90° angle) to a surface, like a mirror, at the point where a light ray hits.