Question

what will be its temperature 5 minutes after reaching 40°C? 

(a) 35°C 

(b) 100/3°C 

(c) 32°C 

(d) 30°C

Answer 1

Correct Answer is: (b) 100/3°C 

If a body cools from temperature θ₁ to θ₂ in time t, when the surrounding temperature is θ₀, by Newton’s law of cooling,

θ₁ - θ₂/t = C [θ₁ + θ₂/2 - θ₀],

where c = constant.