2. •Plato thought that light consisted
of streamers emitted by the eye. it
gained support from Euclid but
was contradicted by Pythagoras as
the latter believed that light
originated from luminous bodies
in the form of a very fine particles .
3. •Empedocles, a forerunner of Plato,
believe that light is composed of
high-speed waves of some sort.
until the beginning of the 20th
century, the real nature of life was a
considerable subject for discussion
among scientists and physicists all
over the world.
4. Wave Theory
•Light has a wave motion which
starts from a vibrating body
and is transmitted at high
speed.
5.
6. Christiaan Huygens
•he proposed that
light consists of a
series of waves
with their
wavefronts at right
angles to put the
race.
7. Huygens’s Principle
•Different points of
wavefronts of light set up a
series of secondary waves
•since light can pass through
a vacuum, he explained that
light may travel through a
medium known as “ether” a
mysterious substance which
is not air .
8. Corpuscular Theory / Emission Theory
•Light consists of
tiny particles of
matter emitted by
a source that travel
only in straight
lines called rays.
9.
10. Max Planck
•Hypothesized that
the vibrating
electrons in
incandescent lights
could only have
energies restricted
to certain values .
12. Quantum Theory of Light
•Albert Einstein
published a novel that
states that light is
composed of bundles of
wave energy called
photons. those findings
supported Planck's
theory .
13. Speed of Light
•The speed with
which light or radiant
energy travels
through space is one
of the precisely
measured quantities
in physical sciences.
14. •Galileo was the first to
hypothesize that light had a
finite speed. Unfortunately, the
immense speed of light calls for
the measurement of its passage
over great distances or the
precise determination up small-
time intervals, are both .
15. OLE ROEMER (1644 – 1710)
•Became the first
person to measure
the speed of light
over an
astronomical
distance.
16. OLE ROEMER (1644 – 1710)
•he made 70 precise
measurements of 42.5
hour I can handle orbital
path of Jupiter's moon ,
Io.
17. •However, the currently accepted
value for the speed of light an
empty space at C as 2.9979 x 10⁸
m/s Was determined through
the experiments conducted by
physicist Albert A. Michelson
(1852 – 1931).
