1. LIGHT WAVES

2. Do you still remember Sir
Isaac Newton? What
about Christian Huygens?
Did you meet them in
your earlier grades? These
people were the first to
study about light.

3. What are the common sources
of light?
How do these common
sources produce light?
What are the common
properties and characteristics
of light?

4. Sir Isaac Newton believed that
light behaves like a particle while
Christian Huygens believed that
light behaves like a wave. A 3rd
scientist, Max Planck came up
with what is now known as the
Dual-Nature of Light. He
explained that light can be a
particle and can also be a wave.

5. To complete our
knowledge about the
nature of light, James
Clark Maxwell proposed
the Electromagnetic
Theory of Light.

6. The Sun for example is known
as a natural source of light.
Sun is also considered as a
luminous body (an object
capable of producing its own
light). Other sources are the
lamps, bulbs, and candles.
These are the artificial
sources.

7. In your earlier grades you learned
about energy transformation.
Energy transformation is
needed to convert or transform
forms of energy to light or other
forms. In bulbs, electric potential
is converted to light. In lamps,
chemical energy is transformed
to light.

8. Spectrum Wheel
 Now that we are familiar with the
electromagnetic spectrum and the
corresponding energies, frequencies
and wavelength probably we can see
some applications of these in everyday
living. UV rays are highly energetic than
other spectral regions on its left. This
could be a possible reason why we are not
advised to stay under the sun after 9:00 in
the morning.

9. Prolong use of mobile phones may
cause ear infection. This may be due
to a higher energy emitted by
microwaves used in cellular phones
than radio waves commonly used in
other communication devices. What
about the visible spectrum? Do you
want to know more about this
spectral region?

10. What are the frequencies
and energies of the visible
spectrum? This is the
visible light. Sir Isaac
Newton used a prism to
show that light which we
ordinarily see as white
consists of different colors.

11. Dispersion is a
phenomenon in which a
prism separates white
light into its component
colors. Dispersion, a
special kind of refraction,
provided us color lights.

12. This phenomenon is observed
when white light passes through a
triangular prism. When white
light enters a prism and travels
slower in speed than in vacuum,
color separation is observed due
to variation in the frequencies
(and wavelength) of color lights.

13. Light
 Light can only travel in a straight
line/path.
 Since light travels in a straight line we
get shadows.
 Speed of light: 300, 000 km/s (highest
speed known in nature) 299, 792,458
m/s or 299, 792.458 km/s
 The farther from the source the lesser
the brightness.