A) \[45.5{}^\circ C\]
B) \[55.5{}^\circ C\]
C) \[65.5{}^\circ C\]
D) \[40.5{}^\circ C\]
E) None of these
Correct Answer: C
Solution :
Let T be the final equal temperature. Heat lost by coffee = Heat gained by cup \[0.3\times {{s}_{coffee}}\times (70-T)=0.12\times {{s}_{cup}}\times (T-20)\] \[\Rightarrow \]\[0.3\times 4080\,(70-T)=0.12\times 1020\times (T-20)\] \[\Rightarrow \] \[4\times 70-4T=0.4T-8\] \[\Rightarrow \] \[T=\frac{288}{4.4}\] \[=65.5{}^\circ C\]You need to login to perform this action.
You will be redirected in
3 sec