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Two bodies, with heat capacities C₁ and C₂ (assumed independent of temperature) and initial temperatures T₁ and T₂ respectively, are placed in thermal contact. Show that their final temperature
T_f is given by T₁ = (C₁T₁ + C₂T₂)/(C₁ + C₂). If C₁ is much larger than C₂ . show that
T_f = T₁ + C₂(T₂ -T₁)/C₁.

User Goaul
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1 Answer

5 votes

Step-by-step explanation:

Given:

  • Initial Temperature of the body(1) with heat capacity
    C_1 is
    T_1
  • Initial Temperature of the body(2) with heat capacity
    C_2 is
    T_2

The heat lost by one body will be equal to the heat gained by other body by first law of thermodynamics.

Let assume that
T_1 is greater than
T_2 and
T_f be the final temperature of both body.


C_1(T_1-T_f)=C_2(T_f-T_2)\\T_f=(C_1T_1+C_2T_2)/(C_1+C_2)\\

If
C_1 is much larger than
C_2 then final temperature
T_f will be


T_f=T_1+(T_2C_2)/(C_1)

User Scott Mitchell
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