An object kept in a large room having air temperature of 25°C takes 12 minutes to cool from 80°C to 70°C.
The time taken to cool for the same object from 70°C to 60°C would be nearly,

Question

Question

Answer 1

CONCEPT:

Newton's cooling is written as;

Here we have T₁ is temperature 1, T1 is temperature 2, K is the positive constant and Ts is the temperature of the surroundings.

CALCULATION:

Given: Temperature T1 = 80°C

Temperature T2 = 70°C

time, t = 12 min.

and the temperature of the surroundings, Ts = 25°C

As we know,

Now, on putting the given values we have;

----(1)

and,

----(2)

Now, on solving the equation (1) and (2) we have;

t = 15 min.

Hence, option 2) is the correct answer.

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