in this video we'll talk about what will happen to the cavity or the cavity inside a metal or or in any material what happens will it increase in size it will decrease or it will remain exactly the same i will begin with the solid let's say you have a solid object and if the volume expansion coefficient here i'm assuming the volume expansion coefficient the beta is greater than zero or positive number when i say the beta our coefficient of volume expansion is positive that means when you increase the temperature it also increases for most of material it does happen but there are some other materials which instead of expanding with the temperature it decreases in size with the increase in temperature and that's not our topic here here we are concerned only with the materials whose sizes or the volume changes with the increase in temperature okay so let's say we have a material here and one after hitting it the size increases that's for the solid object but now if you have a cavity here or if there is no material let's see here what happens the short answer is yes everything including this material and the cavity both will expand but how do you visualize physically or how do you visualize it so let me tell you one thing the cavity in this fear it could be a cylinder or it could be a disc or it could be inside of any metal or any any shape it will exactly change in the with you know exactly expand with the with the change in temperature as a matter if there's a solid objects there okay so this one the rate of expansion of this cavity will be exactly the same as the rate of expansion of this metal here how do you not picture this one so let me give you an example here so let's say we have this cavity here so this this represents a cavity the inner circle here and now assume and this is a material right if it is made of let's say copper so this would be copper here the ring here so here i'm just talking about just taking this ring here and if you unfold this circle or this ring it'll just looks like a line what happens now if you hit it if you hit if you hit it it will expand with the temperature now fold them back and then you'll see a larger circle here so that means the cavity is expanding in exactly a manner manner as a solid expanse okay or what you can visualize here let's say again this is a cavity here if you cut it if you cut it this way and unfold it it would look like this so you have like a plate here and this is slightly curved here now again if you hit it what will happen everything will expand because this is the solid material so it will expand so this this length will expand and this length will expand and now if you fold it back to the circle you will see a lot now a larger cavity a larger circle here so that tells you the cavity expands in a matter in a very in exactly in a manner as a solid object do with the change in the temperature okay so the learning of this lesson is if you have a cavity inside a material then the cavity will expand exactly in a manner as the solid objects will do with the change in the temperature okay so that's a quick video thank you so much again if you have any questions write down your questions in the comment section below and subscribe the channel thank you very much