Reflection — Science definition

Defined in 3 courses:

Where it is taught

In use

When light strikes a surface, the simplest thing it can do is bounce off — reflection.

Reflection, Refraction & Optics

Questions using reflection

Problem 1

Which statement correctly uses normal in Light, Shadows & Reflection?
  1. A visible object must generate its own light.
  2. Reflection angles are defined from the surface rather than the normal.
  3. normal: A line perpendicular to a surface at the point being considered.
  4. One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation

normal: A line perpendicular to a surface at the point being considered.

A line perpendicular to a surface at the point being considered. The correct reflected angle is 40° from the normal and 50° from the surface. Drawing 40° from the surface makes it 50° from the normal, so the mismatch comes from the reference line. These are ideal ray-model angles, not a record of an actual mirror trial.

Problem 2

Which statement correctly uses reflection in Light, Shadows & Reflection?
  1. One illustrative result establishes every real condition and needs no further evidence.
  2. Reflection angles are defined from the surface rather than the normal.
  3. A visible object must generate its own light.
  4. reflection: Light being redirected from a surface.
Answer and explanation

reflection: Light being redirected from a surface.

Light being redirected from a surface. The correct reflected angle is 40° from the normal and 50° from the surface. Drawing 40° from the surface makes it 50° from the normal, so the mismatch comes from the reference line. These are ideal ray-model angles, not a record of an actual mirror trial.

Problem 3

Which statement is scientifically accurate for Light, Shadows & Reflection?
  1. normal: A line perpendicular to a surface at the point being considered.
  2. Reflection angles are defined from the surface rather than the normal.
  3. A visible object must generate its own light.
  4. Every classroom model reproduces reality exactly.
Answer and explanation

normal: A line perpendicular to a surface at the point being considered.

A line perpendicular to a surface at the point being considered. The correct reflected angle is 40° from the normal and 50° from the surface. Drawing 40° from the surface makes it 50° from the normal, so the mismatch comes from the reference line. These are ideal ray-model angles, not a record of an actual mirror trial.

Problem 4

In the law of reflection, the angle of incidence and angle of reflection are measured from…
  1. the horizon
  2. the edge of the mirror
  3. the surface itself
  4. the normal (the perpendicular to the surface)
Answer and explanation

the normal (the perpendicular to the surface)

All angles in optics are measured from the normal, the line perpendicular to the surface at the point of contact.

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