Two systems at same temperature are said to be in

Options

A. chemical equilibrium
B. thermal equilibrium
C. mechanical equilibrium
D. electrical equillibrium

Answer

To solve the question "Two systems at the same temperature are said to be in?", we need to analyze the concepts of thermodynamics, particularly focusing on the conditions under which two systems can be considered to be in equilibrium.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the condition when two systems are at the same temperature.

2. **Identifying the Term**: In thermodynamics, when two systems are at the same temperature, they are said to be in a specific state of equilibrium.

3. **Defining Thermal Equilibrium**: The correct term for two systems at the same temperature is "thermal equilibrium." This means that there is no net flow of thermal energy between the two systems.

4. **Reasoning**: When two systems are in thermal equilibrium, they can exchange heat without any change in temperature. This implies that the systems have reached a state where their thermal energies are balanced.

5. **Conclusion**: Therefore, the answer to the question is that two systems at the same temperature are said to be in "thermal equilibrium."

### Final Answer:
Two systems at the same temperature are said to be in **thermal equilibrium**.