Dois recipientes iguais A e B, contendo dois líquidos diferentes, inicialmente a 20°C, são colocados sobre uma placa térmica, da qual recebem aproximadamente a mesma quantidade de calor. Com isso, o líquido em A atinge 40°C, enquanto o líquido em B, 80°C. Se os recipientes forem retirados da placa e seus líquidos misturados, a temperatura final da mistura ficará em torno de

Let's analyze the situation: we have two identical recipients, A and B, containing two different liquids, initially at 20°C. When placed on a thermal plate, they receive approximately the same amount of heat. As a result, the liquid in A reaches 40°C, while the liquid in B reaches 80°C.

Now, let's think about what happens when we mix the liquids. The final temperature of the mixture will be between 40°C and 80°C, since the liquids were initially at different temperatures. To find the final temperature, we can use the principle of heat transfer.

The correct answer is B) 50°C.

We can explain this by considering the heat transfer between the two liquids. When we mix them, the heat will be transferred from the hotter liquid (B) to the cooler liquid (A) until they reach thermal equilibrium. Since the recipients are identical and the initial temperatures are known, we can assume that the heat transfer is uniform.

Let's denote the initial temperature of liquid A as T_A = 40°C and the initial temperature of liquid B as T_B = 80°C. The final temperature of the mixture, T_f, will be the average of the initial temperatures, since the heat transfer is uniform:

T_f = (T_A + T_B) / 2

T_f = (40°C + 80°C) / 2

T_f = 60°C / 2

T_f = 50°C

Therefore, the correct answer is B) 50°C. This result makes sense, since the final temperature of the mixture is between the initial temperatures of the two liquids.