Transverse Waves (Part - 3) - Waves, Physics, Class 11 Video Lecture -

hello friends this video on waves part 3
is brought to you by exam feel calm
normal fear from exam please make sure
that you have watched all the videos
from part 1 - part 2
before going ahead with part 3 so in
order to study more about mechanical
deals let me tell you about the
classification of waves
there are various categories into which
waves are classified I mean you have you
classify waves into two types on the
basis of something again on the basis of
something else you classify waves into
two types so something like that so
there are many different ways by which
waves are classified so let us look at
this first classification of waves this
classification is on the basis of the
direction of the wave propagation that
is the direction in which the wave is
propagating and the direction of the
disturbance as I told you the wave what
causes the wave a wave is caused by a
disturbance right a disturbance is
initiated and then that disturbance
keeps propagating with time so the
direction of the wave and depending on
the direction of disturbance and the
direction of wave propagation we
classify waves into two types the first
is transverse waves and the second is
longitudinal waves now let us see what
is a transverse wave transverse waves
are the ones in which direction of
disturbance or displacement in the
medium is perpendicular to the
propagation of wave that means the
direction in which the wave propagates
is perpendicular to the direction of
disturbance now if you think of it it is
very easy to remember right direction of
disturbance perpendicular to direction
of wave propagation but think of it
practically I mean try to think of it
that a wave is traveling
do you mean by the direction of
disturbance and what do you mean by the
direction of wave propagation so let us
look at this example to make your
understanding more clear let us suppose
the small little boy is holding this
trend at one end and the other end of
the thread is fixed to the wall now what
happens if you give a jerk to this
thread upward a small job to the thread
upward what happens the entire thread
kind of moves in a wavy manner however
you did not give a jerk at this point at
this point right
you just gave a jerk at one end but this
jerk propagated along the entire length
of the string so this propagation that
is the small disturbance which came from
the source at one end that disturbance
getting propagated so that is known as
the direction of propagation so in this
case what is the direction of
propagation direction of propagation is
this because your wave is propagating in
this direction and what is the direction
of disturbance it is this because the
disturbance was nothing but the
initiator which initiated this small
wavy movement along the red so the
disturbance was initiated in a
perpendicular direction so if you see
the disturbance was vertically upwards
and the wave propagation is horizontal
so that means they are perpendicular to
each other so this kind of a wave is
known as a transverse wave now this was
just an example to make you understand
what is a transverse wave so as I told
you before also how does this wave moves
along the medium I mean what is it that
means this wave to travel along this and
you give a jerk at this end so it would
have stopped here itself why does it
travel at all that was because when we
pull the string upward formation and
propagation
of pulse is possible because this entire
string is under tension let you all know
what this tension because these are all
small terms which I introduced in the
very beginning chapters and now you are
all aware of it so since the string has
a tension because of this tension the
small disturbance which you give at one
end gets transferred to its neighboring
molecules or the neighboring particles
so when they pull one end of the string
it pulls upwards the adjacent section
that means let us suppose you have
pulled it here you pulled it upwards
here
so this pull will cause its adjacent
letters let us let me consider this
letter suppose this is the thread it is
straight now you pulled this part let us
suppose now this pull this thing will
get transferred to its neighboring part
again it will get transferred to its
neighboring part again it will get
transferred to its negative neighboring
part and this way so this small pulse
will get propagated along the length of
the string and this propagation takes
place because of the tension in the
string now as the adjacent section moves
upwards it pulls the next adjacent
section upwards so when this section
moves upwards it causes its next section
that is this dis section to move upward
again this causes the next section to
move upward and so on so this is how the
disturbance gets propagated along the
string so that is how a transverse wave
propagates now let us look at another
example this is how a transverse wave
generally looks like the transverse wave
looks like and up and down up and down
and that helps continue now if you
observe the motion of a particle now
what do you think are all these
particles I mean these particles are
nothing but the particles of the medium
so these as I told you before the
particles are not moving from initial to
final
particle are just moving about their
mean position but the energy is getting
transferred from one particle to another
if you observe this let us suppose this
blue particle this blue point represents
a particle of the medium
now as the wave moves I have just taken
a small part of the wave so as this wave
keeps moving what happens to the
particle how does the particle moves the
particle just moves up and down up and
down up and down however your move wave
is moving in a different way I mean if
you draw this complete wave the wave
propagation takes place along this
direction but the motion movement of the
particle takes place along this
direction right the particle goes up and
down vertically so the movement of the
disturbance or the movement of the
particles of the medium is perpendicular
to the propagation of the wave now let
me also clarify what determines or what
defines the direction of propagation of
the wave direction of propagation is
defined by if you see these waves all
these waves as a whole if you see it in
this way what do you see the wave is
propagating along this direction right
so that is the direction of wave
propagation here now to clarify this
even further because I don't want any
doubt to be there in your mind regarding
these two directions direction of the
disturbance and direction of the wave
propagation let me explain it once again
let us suppose this is a wave right now
how is this wave getting propagated
after some time this wave will go to
this position again after some time the
wave will go to this position and so on
this is how the wave is moving so now if
you compare the first position and the
second position what do you see you see
the particles will move up and down how
let us see here I will draw it once
again let us suppose the
is my initial wave after some time this
waves becomes like this so what happens
the particle which was earlier at this
point is now moved to this point
similarly the particle which was earlier
at this point now moved to this point
similarly the particle which was earlier
at this point now moved to this one so
what do you say the particle is just
moving up and down up and down and so on
this is the best representation to this
have a look at this diagram this is the
best way you can visualize how does a
particle moves up and down
however the wave is propagating what is
one so I hope you are able to understand
what is the transverse mean transverse
wave is the one where the wave
propagates perpendicular to the
direction of disturbance direction of
disturbance is nothing but the direction
of motion of the particles in the medium
also remember that the particles of the
medium doesn't move from initial to
final position they just move about
their own mean position they just keep
moving up and down up and down about
their own position and the energy gets
transferred from one particle to another
and so on thank you please visit exam
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