Electromagnetic waves : Introduction - Physics Video Lecture - Class 12

for the ancients science was grounded in
observation even today many of the
questions science attempts to answer
begin with an unusual sight but we would
not be able to make observations or see
the world at all without light but what
is light we can't touch or taste or hear
it and usually we can't even see light
completely on its own we see light as it
is filtered through the atmosphere and
reflected off different surfaces to
understand light we need to understand a
larger group of energy known as
electromagnetic waves light is a very
small part of the electromagnetic
spectrum and all the types of waves in
this spectrum share certain properties
all forms of electromagnetic energy
including light are waves and as waves
they all have frequency frequency is
usually defined as the number of waves
that pass a certain point in a second
the difference in frequency is a result
of the size of the wave a longer
wavelength corresponds to a lower
frequency electromagnetic waves are
organized in two types based on
frequency at one end of the spectrum are
radio waves which have the lowest
frequency the spectrum moves through
microwaves infrared rays visible light
ultraviolet rays and x-rays two gamma
rays which have the highest frequency