Question

A body cools from 60°C to 50°C in 10 minutes and 50° to 40°C in the next 15 minutes. The room temperature is?​

Answer 1

Explanation:

−dtdT=k(T−To)

(T−T0)dT=−kdt

T= Temp of body

To= Temp. of surrounding =25oC

t=10min=10(60)=600sec

∫5060(T−To)dT=−k[t]o600

k2.303loge[T−To]5060=−k[600]

⇒k2.303loge[50−2560−25]=−600

⇒k2.303loge[2530]=−600            ...(1)

Now suppose for next  to min, temp falls from 50 to T