The frequency of wave is 0.002 Hz. Its time period is

Explanation

To find the time period of a wave given its frequency, we can use the relationship between frequency (f) and time period (T). The formula connecting these two quantities is:

\[ T = \frac{1}{f} \]

Where:
- \( T \) is the time period in seconds,
- \( f \) is the frequency in hertz (Hz).

### Step-by-step Solution:

1. **Identify the given frequency**:
The frequency of the wave is given as \( f = 0.002 \, \text{Hz} \).

2. **Use the formula for time period**:
We know that the time period \( T \) is the reciprocal of the frequency:
\[ T = \frac{1}{f} \]

3. **Substitute the given frequency into the formula**:
Substitute \( f = 0.002 \, \text{Hz} \) into the equation:
\[ T = \frac{1}{0.002} \]

4. **Calculate the time period**:
To perform the calculation:
\[ T = \frac{1}{0.002} = 500 \, \text{seconds} \]

5. **State the final answer**:
The time period of the wave is \( T = 500 \, \text{seconds} \).

### Final Answer:
The time period of the wave is **500 seconds**.