Reflection and Refraction

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Reflection and Refraction
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Angle of incidence angle of reflection
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THE LAW OF REFLECTION

• The angle of incidence is equal to the angle of
  reflection.
• The image in a plane mirror is virtual and is the
  same size as the object.

• Plane mirrors are used in periscopes.
• They are used in rear view mirrors.
• The image is as far behind the mirror is as the
  object is in front.
• Image is laterally inverted

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PERISCOPES
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Shiny smooth surfaces reflect regularly, other
surfaces also reflect light but if the surface is
rough the light is reflected in all directions.
We call this diffuse reflection.
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Diffuse Reflection
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CONVEX AND CONCAVE MIRRORS
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Convex and Concave Mirrors

• A concave mirror is a converging mirror. Parallel
  rays of light are reflected through the focal
  point of a concave mirror.
• A convex mirror is a diverging mirror. Parallel
  rays of light are reflected so that they appear
  to come from the focal point of a convex mirror.

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Uses of Concave Mirrors

• Used to collect light energy, sound, heat,
  radiation, radar and TV signals.
• If you move close to a concave mirror, then you
  see a magnified image of yourself. This image is
  upright and virtual as well as magnified. Shaving
  and make up mirrors

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Uses of Convex Mirrors

• They always produce virtual upright images.
• The image is always smaller than the object.
• They are useful when you want a wide field of
  view car driving mirrors or shop security.

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Refraction

• This is the bending of light rays
• Happens because the rays change speed.
• When they enter a more dense medium (glass,
  water,) they slow down.
• When they enter a less dense medium like air,
  they speed up.

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Total internal reflectionand refraction

• When an object is viewed through water the image
  we see is changed because of the way light waves
  behave as they pass from the water into the air.

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