InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Three metallic spheres A,B and C have their masses in the ratio 1:2:3, specific heat capacities in the ratio 6:3:4. When the initial temperature of the spheres are measrued in Celsius scale, the ratio of their temperature is found to be 1:2:3. Initially the two spheres A and B are brought into contact. when equilibrium temperature is attained, sphere B is brought into contact with 'C'. Determine the ratio of the final temperatures of A,B and C as measured in Celsius scale. |
|
Answer» Solution :Let the masses of A,B and C be m, 2m and 3M the specific heat capacities be 6s, 3s and 4s ad the initial temperatures be t,2t, and 3t SINCE the temperature of A is less than the temperature of B,heat flows from B to A when these two are brough into contact. If `theta_(1)` is the equilibrium temperature, `t lt theta_(1) lt 2t` heat lsot be hot body=heat gained by cold body ltBrgt `therefore(2m)(3s)(2t-theta_(1))=(m)(6s)(theta_(1)-t)` `6(2t-theta_(1))=6(theta_(1)-t)` `2theta_(1)=3t` `theta_(1)=(3t)/(2)` (You MAY observe here that since `m_(1)s_(1)=m_(2)s_(2),Deltat_(1)=t_(2) and theta_(1)` is the average of t ad 2t). Thus, `t_(A)=t_(B)=(3t)/(2)` WhenB and C are brough into contact the equilibrium temperature `theta_(2)` will be greater than that of B `=(3t)/(2)` and less than that of `C(=3t)` Once again heat lost by hot body (C)=heat gained by cold body (B). I.E., `(3m)(4s)(3t-theta_(2))=(2m)(3s)(theta_(2)-(3t)/(2))` `2(3t-theta_(2))=(theta_(2)-(3t)/(2))` `3theta_(2)=6T+(3t)/(2)` `theta_(2)=(5t)/(2)` i.e., `t_(B)=t_(C)=(5t)/(2)` `thereforet_(A):t_(B):t_(C)=(3t)/(2):(5t)/(2):(5t)/(2)=3:5:5` |
|