00:01
Hello guys, so in this question the question is saying about why do the both einstein model of a solid and a dpa model explain the observed violation of the law of doolong and patent what common feature of their densities of state makes this possible so this we have to see an answer of this question is i know a little bit vague but you can write in a language.
00:31
So for this we can say that the both these models agree well at a high temperature limit as they are able to recover due long petition law.
00:47
So in this also see that the report of both of these models this agree at high temperature.
01:06
At high temperature, temperature, temperature limit as they are able to recover, as they are able to recover due long at it low.
01:38
So this is our main line.
01:42
So now we need it and how they counted it at low.
01:46
Temperature limit as experimentally materials so here you can say that by this however they contradict at low temperature they contradict at low temperature limit as experimentally materials as experimentally materials as experimently materials materials like diamond we can say that are found to have their heat capacities proportional to r square their heat capacity are found to have their heat capacity proportional to r so this is the first paragraph who are now moving to the next process an instance model considered that there was only one type of the model of vibration exists within the crystal lattice that contribute to the lattice heat capacity so i can say that only one type of the model is there of vibration exist within the crystal lattice crystal inside the crystal only we have one model of vibrations that contribute to the lattice heat capacity this model is known as optical model so this model is you have to remember that is optical model inside the latest there is a one model of five lines so now seeing ahead more than this model assumed that the energy of optical mode was quantized and so this model is said that this model is this model is assumed that heat is assumed that this model is assumed that heat is quantized so for the quantized process we can say that heat is quantized now going ahead to this question we can say as has no dependence on the momentum is spaces for case space we can show that this model predict that heat capacity will drop exponentially at low temperature so optical model show that this model is stressed that this model expressed that or we can say that predict that heat capacity will drop at low temperature low temperature so this is our second statement now through this though it is incorrect heat capacity at very low temperature so i can write in this language though just a second so it is incorrect it is incorrect it is incorrect fails to describe t to behavior of heat heat you can write here fails fails fails so this describe the tube behavior of heat capacity at low temperature at very low temperature.
07:10
So this is our and it is still a good approximation for static optical phenomenon spectrum.
07:20
Understand? now from einstein model, one can also say that at low temperature it is very difficult to excite an optical phenomenon...
