Transmission Of Heat Question 106
Question: A sphere, a cube and a thin circular plate, all made of the same material and having the same mass are initially heated to a temperature of 1000°C. Which one of these will cool first
[IIT 1972; MP PMT 1993; J & K CET 2000 MH CET 2000; UPSEAT 2001]
Options:
A) Platelet
B) Sphere
C) Cube
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
Rate of cooling $ \frac{\Delta \theta }{t}=\frac{A\varepsilon \sigma (T^{4}-T _{0}^{4})}{mc} $
Therefore $ \frac{\Delta \theta }{t}\propto \frac{1}{A} $ . Since area of plate is largest so it will cool fastest.
BETA
