Ground wave have wavelength

Options

A. a) less than that of sky waves
B. b) greater than that of sky waves
C. c) less than that of space waves
D. d) equal to that of space waves

Explanation

To determine the wavelength of ground waves in comparison to sky waves and space waves, we can follow these steps:

### Step 1: Understand the Types of Wave Propagation
There are three main types of wave propagation in communication systems:
- Ground wave propagation
- Sky wave propagation
- Space wave propagation

### Step 2: Identify the Frequency Ranges
Each type of wave has a specific frequency range:
- **Ground waves** typically operate at frequencies up to 3 MHz.
- **Sky waves** operate at frequencies from about 3 MHz to 30 or 40 MHz.
- **Space waves** operate at frequencies above 30 or 40 MHz.

### Step 3: Relate Frequency to Wavelength
The relationship between frequency (f) and wavelength (λ) is given by the formula:
\[ \lambda = \frac{c}{f} \]
where \( c \) is the speed of light (approximately \( 3 \times 10^8 \) m/s). This formula indicates that wavelength is inversely proportional to frequency.

### Step 4: Calculate the Wavelengths
- For **ground waves** (up to 3 MHz), the wavelength will be maximum because the frequency is low.
- For **sky waves** (3 MHz to 30/40 MHz), the wavelength will be shorter than that of ground waves due to the higher frequency.
- For **space waves** (above 30/40 MHz), the wavelength will be even shorter than that of sky waves.

### Step 5: Compare the Wavelengths
From the analysis:
- The wavelength of ground waves is greater than that of sky waves.
- The wavelength of sky waves is greater than that of space waves.

### Conclusion
Thus, the wavelength of ground waves is greater than that of sky waves. Therefore, the correct answer to the question is:
**B: Greater than that of sky waves.**

---