- Home
- Standard 11
- Physics
10-2.Transmission of Heat
medium
Hot water kept in a beaker placed in a room cools from ${70^o}C$ to $60°C$ in $4$ minutes. The time taken by it to cool from ${69^o}C$ to ${59^o}c$ will be
A
The same $4$ minutes
B
More than $4$ minutes
C
Less than $4$ minutes
D
We cannot say definitely
Solution
(b) Rate of cooling $ = \frac{{ – d\theta }}{{dt}} \propto \left( {\frac{{{\theta _1} + {\theta _2}}}{2} – {\theta _0}} \right)$
In second case average temperature will be less hence rate of cooling will be less. Therefore time taken will be more than $4$ minutes.
Standard 11
Physics
