Q.

A body in a room cools from 85∘c to 80∘c in 5 minutes. The time taken to cool from 80∘c to 75∘c is

Moderate

Unlock the Full Solution and Master the Concept

Get a detailed solution and exclusive access to our masterclass to ensure you never miss a concept

By Expert Faculty of Sri Chaitanya

5 minutes

<5 minutes

>5 minutes

either less or more than five minutes.

answer is 3.

(Detailed Solution Below)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

θ1=85∘c θ2=80∘cθ2=80∘c θ3=75∘ct1=5 minutest2=?θ0=constant=temperature of surrounding from newton law of cooling dθdt1=-kθ1+θ22-θ0---(1) substitute given values in above equationθ1-θ25=-k85+802-θ085-805=-k82.52-θ055=-k41.25-24---(2)∵Room temperature is 24°C second part of question, given values substitute in eqn(1)80-75t2=-k80+752-θ05t2=-k38.75-24---(3) eqn(2) ÷eqn(3) t2= 5.47mint2is more than 5 minutes

Choose your Grade and Exam

Connect with our

Expert Counsellors

access to India's best teachers with a record of producing top rankers year on year.

+91

We will send a verification code via OTP.