The frequency of radio waves corresponding to wavelength of 20 m is

Options

A. ` 3 xx 10^(7) Hz `
B. `1.5 xx 10^(7)` Hz
C. `5 xx 10^(-7) Hz `
D. `3 xx 10^(6) Hz `

Explanation

To find the frequency of radio waves corresponding to a wavelength of 20 meters, we can use the relationship between the speed of light (c), frequency (n), and wavelength (λ). The formula is given by:

\[ c = n \times \lambda \]

Where:
- \( c \) is the speed of light in air (approximately \( 3 \times 10^8 \) m/s),
- \( n \) is the frequency in hertz (Hz),
- \( \lambda \) is the wavelength in meters (m).

### Step-by-Step Solution:

1. **Identify the known values**:
- Wavelength \( \lambda = 20 \) m
- Speed of light \( c = 3 \times 10^8 \) m/s

2. **Rearrange the formula to solve for frequency (n)**:
\[ n = \frac{c}{\lambda} \]

3. **Substitute the known values into the equation**:
\[ n = \frac{3 \times 10^8 \text{ m/s}}{20 \text{ m}} \]

4. **Perform the calculation**:
\[ n = \frac{3 \times 10^8}{20} = 1.5 \times 10^7 \text{ Hz} \]

5. **State the final answer**:
The frequency of the radio waves corresponding to a wavelength of 20 m is:
\[ n = 1.5 \times 10^7 \text{ Hz} \]