Frequency of an E.M. waves is 10 MHz then its wavelength is :

Options

A. 30 m
B. 300 m
C. 3 m
D. None of the above

Explanation

To find the wavelength of an electromagnetic wave given its frequency, we can use the relationship between wavelength (λ), frequency (μ), and the speed of light (c). The formula is:

\[ \lambda = \frac{c}{\mu} \]

### Step-by-Step Solution:

1. **Identify the given values:**
- Frequency (μ) = 10 MHz
- Speed of light (c) = \(3 \times 10^8\) m/s

2. **Convert the frequency from megahertz to hertz:**
- 1 MHz = \(10^6\) Hz
- Therefore, \(10 \text{ MHz} = 10 \times 10^6 \text{ Hz} = 10^7 \text{ Hz}\)

3. **Substitute the values into the formula:**
- Using the formula \( \lambda = \frac{c}{\mu} \)
- Substitute \(c = 3 \times 10^8 \text{ m/s}\) and \(\mu = 10^7 \text{ Hz}\):
\[ \lambda = \frac{3 \times 10^8 \text{ m/s}}{10^7 \text{ Hz}} \]

4. **Calculate the wavelength:**
- Perform the division:
\[ \lambda = \frac{3 \times 10^8}{10^7} = 30 \text{ meters} \]

5. **Conclusion:**
- The wavelength of the electromagnetic wave is \(30\) meters.

### Final Answer:
The wavelength is \(30\) meters.