question_answer 16)

                  Three copper blocks of masses \[{{M}_{1}},\,{{M}_{2}}\] and \[{{M}_{3}}\]kg respectively are brought into thermal contact till they reach equilibrium. Before contact, they were at \[{{T}_{1}},\,{{T}_{2}},\,{{T}_{3}}({{T}_{1}}>{{T}_{2}}>{{T}_{3}})\]. Assuming there is no heat loss to the surroundings, the equilibrium temperature T is (s is specific heat of copper)                 (a) \[T=\frac{{{T}_{1}}+\,{{T}_{2}}+\,{{T}_{3}}}{3}\]                 (b) \[T=\frac{{{M}_{1}}{{T}_{1}}+\,{{M}_{2}}{{T}_{2}}+{{M}_{3}}{{T}_{3}}}{{{M}_{1}}+\,{{M}_{2}}+\,{{M}_{3}}}\]                 (c) \[T=\,\frac{{{M}_{1}}{{T}_{1}}+\,{{M}_{2}}{{T}_{2}}+\,{{M}_{3}}{{T}_{3}}}{3({{M}_{1}}+\,{{M}_{2}}+\,{{M}_{3}})}\]                 (d) \[T=\frac{{{M}_{1}}{{T}_{1}}s+\,{{M}_{2}}{{T}_{2}}s+{{M}_{3}}T_{3}^{{}}s}{{{M}_{1}}+{{M}_{2}}+\,{{M}_{3}}}\]                

Answer:

                  (b) Heat loss/gain \[\propto \] mass of the body and rise or fall in temperature.