Answer:
75.2° C
Explanation:
Given:
mass of the coffee, M = 500
mass of the cup, m = 240
since the coffee is mostly water ,
specific heat of the coffee, C = 4.184 J/kg.°C
specific heat of the aluminium, C' = 0.902 J/kg.°C
The heat lost by the coffee will be transferred to the aluminium cup. The process of heat transfer will continue till the temperature of the coffee and the cup will be in equilibrium (or same)
i.e
Heat lost by the coffee = heat gained by the cup
or
MC(85 - T) = mC'(T - (-20))
where, T is the temperature at the equilibrium or the final temperature
on substituting the values, we get
500 × 4.184 × (85 - T) = 240 × 0.902 × (T - (-20))
or
T = 75.2° C
Hence, the final temperature of the coffee will be 75.2° C
