Manipal MET2018PhysicsLaws of Motion
A body cools in 7 min from 60^ C to 40^ C . What times (in min) does it take to cool from 40^ C to 28^ C , if surrounding temperature is 10^ C ? (Assume Newton's law of cooling)
Options
- A3.5
- B14
- C7
- D10
Correct answer
C. 7
Step-by-step solution
From Newton's law of cooling ₁- ₂ t = ( ₁+ ₂ 2 - ₀ ) Therefore, aligned & 60^ -40^ 7 ( 60^ +40^ 2 -10^ )...(i) & 40^ -28^ t ( 40^ +28^ 2 -10^ )....(ii) aligned From Eqs. (i) and (ii), we get t=7 ~s