Here's how to calculate the wavelength at 4 GHz:

Formula:

* Wavelength (λ) = Speed of light (c) / Frequency (f)

Constants:

* Speed of light (c) = 299,792,458 meters per second (m/s)

Calculation:

1. Convert GHz to Hz: 4 GHz = 4 x 10^9 Hz

2. Plug values into the formula: λ = 299,792,458 m/s / (4 x 10^9 Hz)

3. Calculate: λ ≈ 0.0749 meters

Therefore, the wavelength at 4 GHz is approximately 0.0749 meters or 7.49 centimeters.