What is the frequency of light wave whose time period is `2.0 xx10^(10)` sec

Options

A. `5xx10^(9)` s
B. `4 xx10^(9)` s
C. `5xx10^(-11) s^(-1)`
D. `4xx10^(9) s^(-1)`

Answer

To find the frequency of a light wave given its time period, we can use the relationship between frequency (F) and time period (T). The formula is:

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

### Step-by-Step Solution:

1. **Identify the Given Time Period (T)**:
The time period given in the question is \( T = 2.0 \times 10^{10} \) seconds.

2. **Use the Formula for Frequency**:
Substitute the value of T into the frequency formula:
\[ F = \frac{1}{T} = \frac{1}{2.0 \times 10^{10}} \]

3. **Calculate the Frequency**:
To perform the calculation, we can rewrite the equation:
\[ F = \frac{1}{2.0} \times \frac{1}{10^{10}} = 0.5 \times 10^{-10} \]
To express this in standard scientific notation, we can adjust it:
\[ F = 5.0 \times 10^{-11} \text{ Hz} \]

4. **Final Answer**:
Therefore, the frequency of the light wave is:
\[ F = 5.0 \times 10^{-11} \text{ Hz} \]