A body cools from 600C to 500C in 10 min. If room temperature is 250C. Temperature of body at the endof next 10 min, will be [UP CPMT 2012]

Newton's cooling law is given as θ1−θ2t=kθ1+θ22−θ0Given,   θ0=25∘C,θ1=60∘C,t=10min and θ2=50∘C∴ 60−5010=k60+502−25We get,  k=130 units and t2=10minAgain,  θ2=θ,θ1=50∘C,θ0=25∘C∴ 50−θ10=13050+θ2−25⇒ θ=42.85∘C