REFRACTION - The bending of light as it passes
through a medium
-​ light travels from one medium to another,
changing speed and bending.
-​ light moves at different speeds in different
materials.
-​ Known as the meeting of waves as they travel
along the same medium, this phenomenon is
called interference.
INTERFERENCE - happens when 2 or more waves
overlap, resulting in either constructive interference
(waves amplify each other) or destructive interference
(cancel each other out).
-​ This principle is crucial in understanding
phenomena like sound patterns or light
diffraction.
REFLECTION - light strikes a smooth, flat, and shiny
surface = reflection
-​ light bounces off a surface, such as a mirror,
without being absorbed.
-​ The separation of white light into its constituent
colors is called dispersion.
-​ DISPERSION - light passes through a prism or
other transparent medium, causing the different
wavelengths (colors) to spread out.
-​ separates the light into its colors based on each
color's wavelength.
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WAVE - A wave is a disturbance that transfers energy
through a medium or space.
-​ Waves can be:
1.​ mechanical (requiring a medium like air or
water, such as sound waves)
2.​ electromagnetic (which do not require a
medium, like light waves).
-​ WAVELENGTH The distance between two
consecutive crests or troughs.
-​ measure of how long one cycle of wave,
crest-crest or trough-trough.
-​ important in determining the wave’s
energy, as shorter wavelengths
generally carry more energy.
REFLECTED RAY - The ray of light which leaves the
mirror
-​ When light strikes a reflective surface like a
mirror, it bounces off and travels in a new
direction.
-​ follows the Law of Reflection, which states that
the angle of incidence is equal to the angle of
reflection.
FREQUENCY - The number of waves that propagate in
a unit of time
-​ measured in Hertz (Hz),
-​ indicates how many complete cycles or waves
pass a specific point each sec.
-​ role in determining the characteristics of waves,
such as their pitch in sound or color in light.
-​
CREST - The highest point of a wave
-​ In a transverse wave, the crest is the
point where the wave reaches its
maximum positive displacement.
-​ one half of the full wave cycle
TROUGH - the lowest point of the wave.
A transverse wave produced by vibrating
electric charges is known as a light wave.
LIGHT WAVES Light waves are electromagnetic waves
that do not require a medium and can travel through a
vacuum.
-​ They are a form of energy and include visible
light, radio waves, X-rays, and more.
INCIDENT RAY - The ray of light approaching the mirror
-​ incoming light that strikes a reflective surface,
such as a mirror.
-​ key role in understanding how light reflects, and
the angle it forms with the surface is crucial for
determining the angle of reflection.
SPEED The distance traveled per unit of time
-​ basic concept in wave motion, referring to how
quickly a wave moves through a medium.
-​ The speed of a wave is determined by the
medium through which it travels and is related to
both wavelength and frequency.
-​
ANGLE OF INCIDENCE The angle at which the
wave strikes the surface is equal to the angle at
which it reflects off, ANGLE OF REFLECTION.
SPECULAR REFLECTION - The reflection of light,
when the light reflects in a single direction.
-​ Specular reflection occurs on smooth, shiny
surfaces like mirrors or calm water, where light
bounces back in a predictable direction.
-​ This type of reflection contrasts with diffuse
reflection, where light scatters in many
directions.
CONCAVE MIRRORS - real and virtual image
WAVE THEORY - The study of the behavior of light and
sound waves
-​ Wave theory explains how waves behave,
including concepts like diffraction, interference,
and the relationship between wavelength,
frequency, and speed.
-​ It is essential for understanding phenomena like
the behavior of sound in music and light in
optics.
TRANSVERSE WAVE - A wave that involves the
movement of particles in a direction perpendicular to the
wave’s motion
-​ particles of the medium vibrate at right angles to
the direction in which the wave is traveling.
LONGITUDINAL WAVE - is one in which the particles of
the medium move parallel to the direction of the wave.
-​ particles compress and expand in the same
direction that the wave travels.
-​ has energy transferred in the direction of the
wave.
-​ energy moves along the direction of the wave’s
travel, with the particles in the medium moving
back and forth.
-​ Ex: Sound waves, where the air particles move
in the same direction that the wave travels.
●​ principal ray leaves the object parallel to the
principal axis and passes through the focal point
when reflected.
●​ This rule for ray diagrams states that a ray
traveling parallel to the principal axis of a
spherical mirror will reflect through the focal
point, helping to determine the position of the
image.
CONVEX MIRRORS - produce an image that is always
smaller, upright, and virtual.
-​ image cannot be projected onto a screen as it
appears to be behind the mirror.
-​ lower the index of refraction= less optically
dense the material is.
-​ lower refractive index = less optically dense,
more light
REFRACTED RAY - As light travels from glass to air, the
refracted ray bends away from the normal line.
-​ When light transitions from a denser medium
like glass to a less dense medium like air, it
speeds up and bends away from the normal line,
following the laws of refraction.
Index of refraction formula
SNELL’S LAW
-​ The sine of the angle of incidence (<𝜃𝑖) divided
by the sine of the angle of refraction (<𝜃𝑟) results
in a constant value.
-​ where the ratio of sine of the angle of incidence
to the sine of the angle of refraction remains
constant, and this constant is the refractive
index of the material.
-​ Describes how light bends when passing from
one medium to another, with the sine of the
angles of incidence and refraction having a
constant ratio.
FOCAL RAY - leaves the object and passes through,
reflecting back to the center of curvature.
-​ after leaving the object and reflecting off the
mirror, passes through the center of curvature,
following the laws of reflection in spherical
mirrors.
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Light bends due to changes in speed and direction.
This bending happens due to the difference in optical
densities between the two media.
REFRACTING SURFACE - is the boundary between
two different media where light bends.
INCIDENT RAY - striking two media is reflected back
into the third medium.
-​ This refers to total internal reflection, where light
strikes the boundary between two media at a
certain angle and reflects back into the original
medium rather than refracting through.
-​
As light travels from air to glass, the light travels slower.
When light moves from air (less dense) into glass (denser), it
slows down due to the higher refractive index of glass,
causing the light to bend.