Question

Rate of cooling of a body is \(0.2^\circ \text{C/min}\) when excess temperature is \(20^\circ \text{C}\). The proportionality constant \( k \) is:

• A. \( 0.005 \, \text{min}^{-1} \)
• B. \( 0.01 \, \text{min}^{-1} \)
• C. \( 0.05 \, \text{min}^{-1} \)
• D. \( 0.2 \, \text{min}^{-1} \)

Hint:

Newton’s Law of Cooling is valid for small temperature differences between the body and its surroundings.