Absolute temperature is the temperature at which

Options

A. all molecular motion ceases
B. volume reaches to zero
C. mass becomes zero
D. none of these.

Explanation

To solve the question regarding absolute temperature, we will analyze the options provided and determine which one correctly describes absolute temperature.

### Step-by-Step Solution:

1. **Understanding Absolute Temperature**:
- Absolute temperature is defined as the lowest possible temperature where all molecular motion theoretically ceases. This temperature is known as 0 Kelvin (K), which is equivalent to -273.15 degrees Celsius (°C).

2. **Evaluating the Options**:
- **Option A: All molecular motion ceases**: This is true at absolute zero (0 K), where molecular motion is minimal.
- **Option B: Volume reaches to zero**: At absolute zero, the volume of an ideal gas would theoretically reach zero, but this is more about the behavior of gases rather than a direct definition of absolute temperature.
- **Option C: Mass becomes zero**: This is incorrect; mass does not become zero at absolute temperature.
- **Option D: None of these**: This option is not applicable since we have valid statements in the other options.

3. **Selecting the Correct Option**:
- Based on the definitions and the behavior of matter at absolute zero, the most accurate statement is that at absolute temperature (0 K), all molecular motion ceases. Therefore, the correct answer is **Option A**.

### Final Answer:
Absolute temperature is the temperature at which **all molecular motion ceases**.

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