APPLICATION OF EM WAVES
EM waves
Applications/Uses
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Radio waves
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Radio and television
communication
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Microwaves
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Satellite communication,
terrestrial communications,
RADAR, microwave oven
•
Infrared
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Remote control, infrared
scanner, night- vision google,
autofocus camera,
thermogram
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Visible light
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Photosynthesis, artificial
lighting,
optical fibers in medical uses,
screen of electronic devices
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Sterilization of water from
drinking fountain, check
signatures on a
passbook, used to identify
fake banknotes
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Medical use, engineering
applications
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Medical treatment,
radiotherapy, nuclear
reactions
•
Ultraviolet Rays
•
X-rays
•
Gamma rays
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Reflection - turning back of light rays when it hits a shiny surface like a mirror.
LAW OF REFLECTION
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•
The first law of reflection states that the angle of incidence is equal to the
angle of reflection.
The second law states that the normal line, incident ray and reflected ray all
lie in the same plane.
The Two Kinds of Rays
• Incident ray is the ray of light approaching the mirror.
• Reflected ray is the ray of light which leaves the mirror.
Normal Line - imaginary line that can be drawn perpendicular to the surface of the
mirror and used as reference point in determining the angle of reflection and angle of
incidence
Plane mirrors - exhibits regular reflection where the angle of incidence is equal to the
angle of reflection.
- the type of image is virtual formed behind
Virtual image is an image formed when an outgoing ray from an object always
diverge
- “Not Real” because it cannot be projected
- Image only seems to be there!
Lateral inversion - is a phenomenon wherein what is left on the object appears as
right on the image and vice versa, This is due to the direction that light follows when it
strikes a reflecting surface generally like a mirror.
Real Image – Image is made from “real” light rays that converge at a real focal point so
the image is real
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-Can be projected onto a screen because light actually passes through the
point where the image appears
-Always inverted
curved mirror- is a reflecting surface in which its section is a section of a sphere. There
are two kinds of curved mirrors, the concave and the convex.
•
Concave Mirrors
- Curves inward
- May be real or virtual image
•
concave mirror
-
called converging mirror because the parallel incident rays converge
or meet/intersect at a focal point.
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