Question

According to Newton's law of cooling, the rate of cooling of a body is proportional to $(\Delta \theta {)}^n$ where $\Delta \theta$ is the difference of temperature of body and the surrounding and n is equal to :

• A. 3
• B. 4
• C. 1
• D. 2

Answer 1

Answer: (C)

1

$\frac{d\theta }{dt}\propto (\theta -{\theta }_0)or\frac{d\theta }{dt}\propto \Delta \theta$

We know that from newton's law of cooling $Q=KA\frac{d\theta }{dt}$
So, temperature gradient $\frac{d\theta }{dt}$ will having unity as power.

Therefore, $n=1$