Introduction - Ray, Optics & Optical Instruments Video Lecture - Class 12 | Best Video for Class 12

hello friends this video on ray optics
part one is brought to you by exam
through calm no more fear from exam
topics to be covered in this lesson are
light reflection of light spherical
mirrors refraction of light total
internal reflection refraction at
spherical surfaces refraction by lenses
refraction through prism dispersion of
light and optical instruments which
could include eye microscope and tell us
for so ray optics what do you think we
are going to study in this lesson okay
when we talk when we hear the stumped
optics what comes to your mind
optics something related to optical
instruments right which which you often
use I mean you use these stones in your
day-to-day life right optical
instruments reminds you of your glasses
spectacles right so that means we are
going to study about certain phenomenon
related to light we have already spoken
about electromagnetic waves right
electromagnetic spectrum where we have
talked about light as such I mean we
have seen what is light what is light
composed of so how is light an
electromagnetic wave so now we have
already has that introduction of light
when we studied the lesson on
electromagnetic waves so in this lesson
our target is to study certain
phenomenon of light so we will study
about some of the phenomenon right for
example reflection of light refraction
of light so I mean right now I mean
these terms are not very new to you you
would have studied about reflection and
refraction in your junior classes maybe
in class
into class 10 so I mean this is not
exactly new for you but we will study
these phenomenon again in a bit more
details we will also study about certain
things or certain objects which enhance
such properties of light right so now
you will gradually see there are so many
things which we are going to study in
this lesson which you will gradually see
as we proceed with the chapter so our
aim is here to study about certain
important phenomenon related to light
and also to see how do these phenomenon
actually help us in our day-to-day life
that is we will relate this phenomenon
with practical applications in life
right so let us look at this interaction
screen what do we have here here as
always that is the general trend right
how we start a lesson the introduction
page will consist of certain things
which we see around us and which is
related to what we are going to study in
this lesson so what you see here
something dark
right it looks like somebody is standing
there but when the light is switched on
in the room you can see oh the sepoys
standing inside the room so that means
like to something which enables you to
view objects you are seeing so many
beautiful things around you because of
reflection of light now what does this
reflection actually we will study about
that as we go ahead
so some similar applications which we
use in our day-to-day life but we don't
know how it actually works what is the
physics behind it for example the
mirrors which we use in our home not
only the normal clean mirrors which are
normally seen in your dressing tables
but also your shaving mirrors they are
different from your plane mirrors right
when you come I mean when you come very
close to the shaving mirror you can see
your face very clearly and you can see
an enlarged image of your spirit of your
face right the spectacles I mean most
you would have seen a spectacle some of
you have been maybe you are using a
spectacle so they are all applications
of what we are going to study in this
lesson the rearview mirror used in your
cards you would have seen
while you are on the driver's seat or
while somebody is driving a car there is
a mirror on this right hand side I mean
there is a rear back view mirror which
enables you to see the traffic which is
coming behind you right the telescope
which enables you to see objects which
are far away from you specially there
are certain different types of
telescopes which also help you to see
the heavenly objects so this is also
some of the telescope's are also used
for scientific purposes for studies of
astronomia and things like that the
camera lens so even the lens the glass
this kind of lens mirrors they are all
nothing but application of such
phenomenon of light the microscope which
enables us to see is very small objects
so basically these instruments like
microscope telescopes they always
consist of lenses right and what are
these lenses these lenses are nothing
but they are all applications of this
reflection or refraction of light so so
that's how we will study this lesson on
we will start with light then we will
talk about the different phenomena like
a reflection of light refraction of
light then we will talk about mirrors we
will talk about spherical mirrors what
are then you will come to know very soon
then we will talk about lenses then
we'll talk about how refraction takes
place through lenses then we'll also
talk about prisms so there are there is
a huge list which we will be talking
about while you go ahead with this
lesson so just be patient and let's now
start with the lesson
so the first screen talks about what is
light nothing new because we have
already talked about it before light is
something which enables us to see
objects so when we talked about electrum
you remember the electromagnetic
spectrum which we talked about which had
so many different kind of light
I mean waves gamma rays x-rays
ultraviolet and here is your visible
light so in this lesson our focuses only
on this visible region so this visible
light is often known as let right so we
are in this entire lesson we are just
focusing on this portion of the ultra of
electromagnetic spectrum so light is an
electromagnetic wave now what is an
electromagnetic wave I don't think I
need to explain that again
because we have already had a detailed
discussion on electromagnetic waves in
our previous lesson so light travels
along straight paths these are some of
the things which are just for review
right because you already know all these
things in your from your previous
classes right that light travels along a
straight path speed of light is
measurable and the speed of light in
vacuum is always denoted by C and its
magnitude is 3 into 10 to the power 8
meter per second so these are some of
the facts about light which you already
know and which are universal right now
when I talk about light as I will go
ahead with the lesson you will see that
most of the times I use such terms like
a ray of light is coming in a ray of
light is going out so what actually is a
ray of light similarly you will also
come across terminal-a is like a beam of
light is falling on a piece of paper so
what do you think what is a ray of light
and how is it different from a beam of
light is there any difference between a
ray of light and
Rema plant or both are the same because
if literally you look at the meaning of
array and a beam generally we think that
both are same but actually here when I
talk about a ray of light I am talking
about the path of light wave traveling
from one point to another let us suppose
this is one point this is not the point
and this is my light wave so the path of
the light wave from this point to this
point so this is the path right so we
say that this is a ray of light life
because my light wave is somewhat like
this let us assume so this light we have
traveled from this point to this point
so what is my ray of light so we say
that this is my ray of light so the
light ray of light is not the light
actually light itself it basically shows
that this is the path through which the
light will traveled right so this is my
ray of light now what is a beam of light
then beam of light is nothing but a
bunch of rays of light that means when
too many rays of light are traveling
very closely we see that this entire
thing is a beam of light right so if you
look at this picture what does this
picture depicts it is depicted nothing
but the Sun a beam of Sun grains is
falling on this tree so here many rays
together are forming a beam of light so
now you know the difference between a
ray of light and the beam of light so
now you will see that as we go ahead
with the lesson most of the time I will
be saying that okay so a ray of light is
incident on the surface our ray of light
is falling on this boundary so when I
say a ray of light I will often draw a
straight line that doesn't mean that
light wave has now become straight
because you have seen in the lesson on
electro
that waves means the wavy thing which I
have shown here so this is how the light
wave is actually traveling but whenever
I I look at I will look at things like
reflection refraction and all instead of
drawing this wave and always considered
the ray of light so which will make my
diagram minute easy to understand and at
the same time it will make it less
complicated right so now you know what
is a ray of light no confusion
difference between a ray of light and a
beam of light right okay thank you
please visit
examview dot-com to watch free
educational videos try3 online tests get
the best quality study materials study
from the best tutors and mentors and
much more thank you once again