NEET-XI-Physics
exam-2 year:2016
- #127Two identical bodies are made of a material for
which the heat capacity increases with temperature.
One of these is at 100 °C, while the other one is
at 0°C. If the two bodies are brought into contact,
then, assuming no heat loss, the final common
temperature is :-
(1) less than 50 °C but greater than 0 °C
(2) 0 °C
(3) 50 °C
(4) more than 50 °CdigAnsr: 4Ans : (4)
Sol. Let be the final common temperature. Further,
let sc and sh be the average heat capacities of the
cold and hot (initially) bodies respectively (where sc
< sh given)
From, principle of calorimetry,
heat lost = heat gained
sh(100°C - ) = sc
∴ = h
h c c
h
s 100 C
100 C
(s s ) s
1
s
=
+
+
sc / sh < 1 ∴1 + sc / sh < 2
∴>
100 C
or > 50°C
2