Certain quantity of water cools from 70° C to 60° C in the first 5 minutes and to 54°C in the next 5 minutes. The temperature of the surroundings is:-
Answer & explanation
Correct answer: option 1
\(\frac{T_1 + T_2}{\Delta t} = k[\frac{T_1 + T_2}{2} - T_o]\)
i) T1 = 70°C ; T2 = 60°C
⇒ \(\frac{10}{5} = k[65 - T_o]\)
ii) T1 = 60°C ; T2 = 54°C
⇒ \(\frac{6}{5} = k[57 - T_o]\)
To = 45°C