MHT CET202616 April 2026Evening ShiftPhysicsThermal Properties of MatterActual
A bowl filled with very hot water cools from 98^ C to 86^ C in 2 minutes when the room temperature is 22^ C . How long it will take to cool from 75^ C to 69^ C ?
Options
- A0.5 minute
- B1.4 minute
- C1 minute
- D2 minute
Correct answer
B. 1.4 minute
Step-by-step solution
Using Newton's law of cooling: T₁ - T₂ t = K ( T₁ + T₂ 2 - T₀ ) For the first case: 98 - 86 2 = K ( 98 + 86 2 - 22 ) 6 = K (92 - 22) 6 = 70K K = 3 35 For the second case: 75 - 69 t = K ( 75 + 69 2 - 22 ) 6 t = K (72 - 22) 6 t = 50K Substituting the value of K : 6 t = 50 3 35 6 t = 30 7 t = 42 30 = 1.4 minutes Answer: 1.4 minute