Am I audible guys? Yes sir So, write it down Barometer Write it down It's a scientific instrument It is a scientific instrument used to measure atmospheric pressure. Guys, they go.
For example, take a glass tube. Take a glass tube of barometer. Fill a liquid in the glass tube. Fill the entire liquid up to the top level.
Generally, mercury barometer is commonly used. So, the liquid is mercury. Any other liquid can also be used. You will know why mercury is used in a while. You took this and then you took another container.
and in which there is mercury, what you did is, this which you have filled with mercury till this level, why you filled with liquid so that there is no air inside, if by chance you have left its level below, then what will happen here at that time? Clear. Clear? Yes, clear sir. Now what you did is, you lifted it and set it up on top of it.
So this is something like this. Now what will happen in this? This level of mercury, let us say, is up to here.
And what will happen here? Can you tell us? It will be vacuum. What will happen here?
It will be vacuum. It will be vacuum here. You have made this level like this. It will be vacuum here.
Now, let us say this height, let's assume this is h. We have taken h height. Okay.
We have taken h height. Now, liquid. You should have an idea of the pressure variation in the equation. Suppose this is liquid.
Suppose you take a point here and a point here in the equation. So, these two points are A and B. So, pressure at A will be equal to pressure at B.
Did you understand? Yes, sir. But if you have taken pressure at B, You know, if you go to the depth, let us say this is point C, then the pressure at C will be plus something or minus something? Plus something.
This is because of the liquid above it, right? So you wrote plus something. What is for gas?
What do you call for gas? This. Suppose you have taken gas in a container.
So you are measuring pressure here or here. What will be the pressure for you? Same.
Same. Same. Same.
Same. Right? Now let's come here. Again. So, let's assume that you took point A here.
Here you have taken point A. Here you have taken point B. Okay.
So, the point A is in the contact of the atmosphere, right? So, that will be atmospheric pressure. Am I clear? Yes, sir. And the point B is vacuumed here.
whatever pressure is because of this liquid am i clear yes sir so this liquid is applying how much force yes sir can we write force per unit area clear evada yes sir We can show it roughly. Okay. Okay.
This mass, let's assume that the density of the liquid is rho. Density of the liquid. Density is rho. So, what can we write for this mass? Density into?
Volume. Am I clear? Are we going correctly? Yes.
Okay. This volume, what will be this volume? Cross-sectional area. Cross-sectional area into this height you have written. Am I clear?
Yes. This will be it. So, substitute here. So, this will be rho into h into g okay, so 1a here here a into h into g upon a a will get cancelled did you understand? yes okay so this will be your let's write it in standard way h rho g did you understand?
at which point is this pressure? b b or liquids with the help of this Sir, I am not able to speak. Sir, I am not able to speak. Your voice is breaking.
Speak to the mic or guide someone. Sir, I am not able to speak. What is mercury and what is water?
There is no water in it. It is mercury. Okay.
Sab Mercury hi hai. Theek hai? People don't want to go to the movies.
They don't want to go to the movies. They don't want to go to the movies. They don't want to go to the movies. They don't want to go to the movies.
They don't want to go to the movies. Sir? Yes?
He is saying, if I walk this street, will you talk to me please? Sir, you go. I am going to go.
How did H.R.O.G come? Yes sir. Can you explain it again? How did H.R.O.G come?
Yes sir. So did everyone copy this? Yes sir.
So write a few points first then we will discuss it again. Ok? Will you write? Yes sir. The variations of The variations of pressure in different directions in a fluid is examined by Pascal's law.
You will study this in fluid mechanics. I am just telling you this so that you can get the questions. Now what does it say?
Write that. In a fluid at rest in a closed container, a pressure change in one part... pressure change in one part is transmitted without loss to every portion of fluid.
And to the walls of the container. Iske niche likhi ga. Three important points. Three important points. For liquids at rest.
Three important points. For liquids at rest, pressure at a point is same in all directions. Point number two, pressure is same, pressure is same on all points, pressure is same, pressure is same at all points on the same horizontal level.
Pressure is same at all points on the same horizontal level. further you're right pressure increases with depth remember this let's repeat it we selected two points now see what is written in one of the three important points same horizontal so pressure will be same am I clear? so here this is directly in the contact of atmosphere so pressure is PA that is equal to atmosphere pressure now this is we have seen how they extract the pressure from the liquid that whatever pressure is coming here is because of this liquid this weight will be coming because of this liquid yes sir ok so we can write it here force per unit area so what will we write here? mg ok this is very you know but still the result will come out anyway. How will we get the mass?
If we have given the density of the liquid, then we will say density into volume, that is the mass. How to get the volume? It is very easy.
Suppose your liquid is here and you have taken H-I-T. So, the volume will be cross-sectional area into this height. That is what is written. A into H.
Clear? Yes, sir. And G is already kept here.
Now, A and A will get cancelled. What is left? Rho Hg, which I have written as H rho G. Clear?
Yes, sir. Yes. So, you both equate the value of atmospheric pressure. You will get the value of H rho G.
Any confusion? Remove this? Remove this?
Yes. Now, assume... Now, as you have seen that we use Mercury barometer, so why Mercury liquid?
Why don't we take any other liquid? You will know that now. Let's say I give you this.
For example, let us say P atmosphere. Let's say the atmospheric pressure is given as 1 atm. The atmospheric pressure is given as 1 atm. Okay? 1 atm is given.
And... Do you know the relation between atm and Nm2? Yes, I know. Now, if you have the atmospheric pressure and the mercury liquid If we give its density 13.6 gm per cubic centimeter, can you calculate the height of the mercury column?
Yes sir. It's very deep. Please calculate and tell me.
So, we're going to go ahead and start recording. And we're going to go ahead and start recording. So, we're going to go ahead and start recording.
And we're going to go ahead and start recording. So, we're going to go ahead and start recording. So, we're going to go ahead and start recording. So, we're going to go ahead and start recording. So, we're going to go ahead and start recording.
So, we're going to go ahead and start recording. Units ka dhyan rakhna hai bida. Nein toh kya bata jayega.
Units ka hiyal rakhna. Sir, 0.071 centi meter. Who put this?
Sir, I put Newton per centimeter square. You have messed up some units. You couldn't do the units properly. I have to go to the hospital.
I have to go to the hospital. If you want to convert gram per cm cube into kg per m3, then you will multiply 10 raised to minus 3. How much will you multiply for this? 10 raised to minus 6. So, how effective will it be? 13.6 into 10 to the power 3 kg per m3 to convert into SI unit. I don't understand.
He is asking for one minute. substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute substitute And the density is 13.6 x 10 to the power 3. And how much will you keep the value of G? One minute. What was he saying?
No, sir. You are asking for forgiveness. How much value does it get?
Can anyone get the value? 10 by 13 meter How much? 10 by 13 meter Tell me the value Sir, 7.5 or something 7.5 or something So, we are doing the same thing This much should come, see Is it enough?
Yes, sir 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm 76 cm I hope you understand what I am saying. And you guys write this as 760 mm of Hg. Have you forgotten? This is the one that relates to the atmosphere.
I hope you understand what I am saying. This is the one that relates to the atmosphere. Yes sir.
Yes sir. Now do one thing, you have taken out this. Now do one thing, take water here instead of Hg liquid.
Take water here and how much density will you take of it? 100 kg per liter. Absolutely right.
Now, let's see the height of the water column. Let's take an imaginary situation. We have taken the liquid as water. You will also know why water is not taken. Let's see the value of the liquid.
hello or that will be equated with H you have to subtract, the value of rho is 1 into 10 to the power 3 and this is 9.8. So, the value of H, how much did you subtract? 10 meters, right?
10 meters. Maybe I have given 9.88 meters. Yes, you have given 9.88 meters.
So, now you see, are you trying to understand 9.88? Are you trying to understand 9.88? If you use a column, its length, you imagine how much it should be?
This is the length. The tube you are taking, can you understand the length of that tube? Is this practically possible? Yes, it is. That's why we use mercury, because of its density.
Ayub, can you understand my point? Yes, yes. Okay, this. So, one important point is this, in future you can do it like this, rather than using that P is equal to rho gh, you can equate it like this, it's like density of mercury column into height of mercury column is equal to density of, you know, any other liquid into the height of that liquid column.
Did you understand? Yes sir. So if you know 76 cm or 0.76 m, then substitute here, keep the density of mercury, keep the density of water, you will get the answer directly from here.
Did you understand? Yes sir. This is another way.
You can also use another way of finding the water column height or any other liquid column height. welcome why do we use mercury as a liquid in you know barometer So, we use Mercury barometer. Now, let's draw the barometer setup.
What we did was, Let us say, this column is visible from here. You have identified two points A and B. Of course, pressure at point A is equal to pressure at point B.
Okay. Now what we considered here is that vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum vacuum pressure at B pata chalega. Okay.
Toh yahaan par jo aap pressure A likh rahe ho. Yeh toh simply kya ho jayega. Atmospheric pressure.
Lekin yeh jo B hai. That will be pressure of air plus H rho G. Kya baat samush mein hai bida? Air hai. Toh yeh jo yahaan par aap aap isko jara use karke dekho.
and tell me, if by chance we do a comparison of this case, with the case where there was a vacuum, if in that case, when the case with the vacuum came, what would be the relation between the two? Sir, one thing is clear, that the one with the vacuum... I am saying, the barometer you took, We have put air in this barometer.
You can call it a faulty barometer. Here is the air. How can air come?
Suppose you have put mercury liquid in the glass tube. You have not filled it up to here. So what is here at this time? Air.
So basically air will go up, right? So air will come there. So the pressure due to that and the column will also give you pressure.
My question is that when we were taking vacuum, if the height of the column was h at that time, and when we took the case of air, we took faulty barometer, 2h'came, then tell h and h'. what will be the relation between H'and H'? H'is equal to H'or equal to H'? H'is equal to H'Is it clear to everyone? Yes sir So write H'very easily and it will be PATM minus PAR upon rho g n that is h dash.
When h was what? h was p atm upon rho g h. What will happen? That will be greater than h dash.
Is it clear? Is there any confusion? Yes.
a concept of manometer another instrument that is used to measure pressure that is used to measure pressure of gas in the container of gas inside the container guys This is the open end. Tell me, let's say this point A is the same horizontal as this point B. So, can I say PA is equal to PB?
Yes, it is equal to PB. here is a gas in front of us let us say gas this is the pressure because of gas have you clear? at point A above this what is it? it is only gas so we will write pressure of gas X is it clear? and and and here we have this pressure at B why is it?
Atmosphere and atmosphere are not the same. Everyone is clear that atmosphere pressure will not come only. Yes sir. Right?
And it will also come from the height. So we will write it. Atmospheres rho g.
Everyone is clear about this. Take care of units whenever you solve questions in the future. So basically This helps you to get the pressure of gas X Is it clear?
Now tell me At this time the pressure of gas X That is less than atmospheric pressure or less than atmospheric pressure? Yes, director. Director?
Maths is also wrong. Maths? No, no.
So many people said this for the first time. See, many people's maths is wrong. Study, son, study.
No, I don't know how to read. Tell me this. Guys, leave all that. Don't fight.
Now tell me, if I take a container like this, the container has become thin, you guys fix it. And I have put it in this, you know, this time the height is more up here. We took the same gas inside.
gas let us say x so now we will do what? on the side here let us assume when you use it here I will write it for that you will use it so left hand side means which is at a pressure at a because of which it will be pressure of gas x plus h rho g Sir, you have some medical issue. Open and direct?
What will happen? Sir, what happened? Sir, you have some medical issue.
You have some medical issue. Sir, you have some medical issue. Sir, you have some medical issue. Guys, can you hear me now? Yes, we can hear you.
Now, tell me, where did you come from? I came from the starting field. The second one was... Oh, you had drawn a figure.
Did you see it? Yes, I saw it. The first one was... The second one was...
I saw it from here. Yes, I saw it. Your math was not good till here.
You couldn't see this, right? Yes, I saw it. So I was saying that the point B was liquid and Mercury was present. Now you are considering another case where you have filled the gas X. and connect it to the manometer here we will take this understand this point is B this point is A and this is open end here is gas X so you can say sorry we will not take A here we will take it at the same height, liquid is till here and take point A because there is atmospheric pressure on point B because there is no liquid on it what will be the pressure of point A?
gas pressure plus liquid pressure plus and what else? H2O3 Gas pressure plus H rho g. Is the sound coming now? Yes. The sound is coming properly.
The sound is coming properly. Yes. The network is there.
Px plus H rho g is equal to P atm. So, from here, tell me that Px is greater than P atm. What is coming out here?
P atm is greater than Px. I think that's a good question. I think that's a good question.
I think that's a good question. I think that's a good question. I think that's a good question.
I think that's a good question. I think that's a good question. I think that's a good question. I think that's a good question. I think that's a good question.
I think that's a good question. I think that's a good question. I think that's a good question.
I think that's a good question. Did you copy that son? Yes, I did copy that son. So, you have to be careful with this. It doesn't matter that you have drawn this.
So, these two arms, no matter how thin or thick they are, it doesn't matter. Suppose I made it like this and made it like this. So, it doesn't matter. height matter is it clear? yes sir ok, let's finish all this yes sir now let's see how much your mind is working ok sir come on I think it's a little bit of a thing that's connected to the problem.
Yeah. So I think that's a big thing. I think that's a big thing.
I think that's a big thing. I think that's a big thing. I think that's a big thing. I think that's a big thing.
I think that's a big thing. I think that's a big thing. I think that's a big thing. I think that's a big thing.
I think that's a big thing. I think that's a big thing. I think that's a big thing.
I think that's a big thing. I think that's a big thing. I think that's a big thing.
I think that's a big thing. I think that's a big thing. I think that's a big thing.
I think that's a big thing. I will show you how to do it. So that you can do it.
Yes, sir. Let's see. Now, as you have given the question, you directly ask the question. Is the sound coming now? I was saying that if I ask a question directly, what is the pressure of ammonia gas?
So you would have answered 76 cmHg 180 m, right? Yes sir. He will answer, who has a light manometer idea.
That's why he gave the equation intentionally. Now what will you do? When you write this equation, 2ns3 giving n2 plus h2, 3h2, then we can write this.
Initially, we will write 76 cm of hg or 1 atm. What will we write? 76 cm of hg.
Initial. Is there any problem? Is initial only ns3? Recall the concept of MOL Yes Sir Suppose there is a dissociation After dissociation, suppose there is a decrease in the amount of 76 Suppose the basis of the coefficients given is 76 yeah so how much will be N2?
how much will be H2? is it clear? yes sir 76 plus 2P any difficulty? is it clear? 76 plus 2P and he is saying that how much difference it makes later 6 cm so what is the reason for that This means we can keep 2P is equal to 6, right?
And P's value 3 came, centimeter of HG. Is it clear? Yes, sir. So if P's value 3 came, then he said, tell me partial pressure of H2, which is what?
3P. So tell me what the answer will be? 3P.
Did you understand the answer? Yes, sir. This question was not that difficult.
This question was not that difficult. you move down it's not done? yes it's not it's the same the same see this is coming ok ok ok ok so guys Pahla question hai naa, ispe wo jo maine another approach bataya tha naa, another way to find answer.
Yad hai? H-Row is equal to H-Row. Pahle wale mein vahee tarika lignan.
Pahle question ke ki answer aaya bida?