1. Concept:According to the Zeroth Law of Thermodynamics, two systems in thermal contact will exchange heat until they reach thermal equilibrium, at which point their temperatures must be exactly equal.
2. Formula:$$T_A = T_B = T_{\text{equilibrium}}$$
3. Solution:- Heat will flow from the hotter body (A) to the colder body (B).
- This flow continues until the temperatures equalize.
- Looking at the options, the only mathematical state where \(T_A\) exactly equals \(T_B\) is \(45^\circ \text{C}\). The specific final value depends on mass and specific heat, but equality is strictly required.
4. Why other options are incorrect:Options with unequal temperatures signify that thermal equilibrium has not yet been reached and heat is still flowing.
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