Q. A body takes 5 minutes for cooling from $50℃$ to $40℃$. Its temperature comes down to $33.33℃$ in next 5 minutes. Temperature of surroundings is
A) $15℃$
B) $20℃$
C) $25℃$
D) $10℃$
Explanation
(b) In first case $\frac{50 - 40}{5} = K\left\lbrack \frac{50 + 40}{2} - \theta_{0} \right\rbrack$ …(i)
In second case $\frac{40 - 33.33}{5} = K\left\lbrack \frac{40 + 33.33}{2} - \theta_{0} \right\rbrack$ …(ii)
By solving $\theta_{0} = 20℃$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.