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 frequency (f), wavelength (λ), and the speed of light (c). The formula is:

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

### Step-by-Step Solution:

1. **Identify the given frequency**:
The frequency of the electromagnetic wave is given as 10 MHz. We need to convert this into hertz (Hz) for our calculations.
\[ 10 \text{ MHz} = 10 \times 10^6 \text{ Hz} = 10^7 \text{ Hz} \]

2. **Use the speed of light**:
The speed of light (c) in a vacuum is approximately:
\[ c = 3 \times 10^8 \text{ m/s} \]

3. **Rearrange the formula to solve for wavelength (λ)**:
From the formula \( f = \frac{c}{\lambda} \), we can rearrange it to find λ:
\[ \lambda = \frac{c}{f} \]

4. **Substitute the values into the equation**:
Now we can substitute the values of c and f into the equation:
\[ \lambda = \frac{3 \times 10^8 \text{ m/s}}{10 \times 10^6 \text{ Hz}} \]

5. **Simplify the equation**:
\[ \lambda = \frac{3 \times 10^8}{10 \times 10^6} = \frac{3 \times 10^8}{10^7} = 30 \text{ meters} \]

6. **Final answer**:
Therefore, the wavelength of the electromagnetic wave is:
\[ \lambda = 30 \text{ meters} \]