Why is the ratio of two extensive quantities always intensive?












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Is this something that we observe that always happens or is there some fundamental reason for two extensive quantities to give an intensive when divided?










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    3












    $begingroup$


    Is this something that we observe that always happens or is there some fundamental reason for two extensive quantities to give an intensive when divided?










    share|cite|improve this question









    $endgroup$















      3












      3








      3





      $begingroup$


      Is this something that we observe that always happens or is there some fundamental reason for two extensive quantities to give an intensive when divided?










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      $endgroup$




      Is this something that we observe that always happens or is there some fundamental reason for two extensive quantities to give an intensive when divided?







      thermodynamics soft-question definition






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      asked 40 mins ago









      paokara moupaokara mou

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          It is mainly a mathematical reason. Extensive quantities grow with system size. If two quantities scale in the same way with a variable (in this case system size), it cancels out in the division.



          Mini-example: $A$ and $B$ are extensive physical quantities both dependent on $n$. Their ratio is called $C = A / B$. If you scale the system up, $A$ and $B$ grow by a factor of $n$. What happens to $C$?



          $frac{A cdot n}{B cdot n} = frac{A}{B}$



          $C$ stays the same, irrespective of $n$. Hence, $C$ is intensive. The most common physical example is mass and volume, which scale with system size and still exhibit the same ratio, the density.






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            $begingroup$

            It is mainly a mathematical reason. Extensive quantities grow with system size. If two quantities scale in the same way with a variable (in this case system size), it cancels out in the division.



            Mini-example: $A$ and $B$ are extensive physical quantities both dependent on $n$. Their ratio is called $C = A / B$. If you scale the system up, $A$ and $B$ grow by a factor of $n$. What happens to $C$?



            $frac{A cdot n}{B cdot n} = frac{A}{B}$



            $C$ stays the same, irrespective of $n$. Hence, $C$ is intensive. The most common physical example is mass and volume, which scale with system size and still exhibit the same ratio, the density.






            share|cite|improve this answer









            $endgroup$


















              4












              $begingroup$

              It is mainly a mathematical reason. Extensive quantities grow with system size. If two quantities scale in the same way with a variable (in this case system size), it cancels out in the division.



              Mini-example: $A$ and $B$ are extensive physical quantities both dependent on $n$. Their ratio is called $C = A / B$. If you scale the system up, $A$ and $B$ grow by a factor of $n$. What happens to $C$?



              $frac{A cdot n}{B cdot n} = frac{A}{B}$



              $C$ stays the same, irrespective of $n$. Hence, $C$ is intensive. The most common physical example is mass and volume, which scale with system size and still exhibit the same ratio, the density.






              share|cite|improve this answer









              $endgroup$
















                4












                4








                4





                $begingroup$

                It is mainly a mathematical reason. Extensive quantities grow with system size. If two quantities scale in the same way with a variable (in this case system size), it cancels out in the division.



                Mini-example: $A$ and $B$ are extensive physical quantities both dependent on $n$. Their ratio is called $C = A / B$. If you scale the system up, $A$ and $B$ grow by a factor of $n$. What happens to $C$?



                $frac{A cdot n}{B cdot n} = frac{A}{B}$



                $C$ stays the same, irrespective of $n$. Hence, $C$ is intensive. The most common physical example is mass and volume, which scale with system size and still exhibit the same ratio, the density.






                share|cite|improve this answer









                $endgroup$



                It is mainly a mathematical reason. Extensive quantities grow with system size. If two quantities scale in the same way with a variable (in this case system size), it cancels out in the division.



                Mini-example: $A$ and $B$ are extensive physical quantities both dependent on $n$. Their ratio is called $C = A / B$. If you scale the system up, $A$ and $B$ grow by a factor of $n$. What happens to $C$?



                $frac{A cdot n}{B cdot n} = frac{A}{B}$



                $C$ stays the same, irrespective of $n$. Hence, $C$ is intensive. The most common physical example is mass and volume, which scale with system size and still exhibit the same ratio, the density.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 31 mins ago









                lmrlmr

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