In free space, which factor is used to determine wavelength from a given frequency?

In free space, which factor is used to determine wavelength from a given frequency?

• A. The speed of light
• B. The impedance
• C. The magnetic field
• D. The temperature

Answer: (A)

Wavelength in free space is determined by how fast the wave travels and how often cycles occur. Electromagnetic waves in vacuum travel at the speed of light, c, so the relationship is lambda = c / f. Knowing the frequency lets you divide the speed of light by that frequency to get the wavelength. This speed is a constant for free space, coming from Maxwell’s equations, so the wavelength is fixed by c and f. The impedance of free space is a ratio between electric and magnetic fields, not a factor that sets wavelength. The magnetic field amplitude or temperature don’t determine the wavelength in vacuum either.

Wavelength in free space is determined by how fast the wave travels and how often cycles occur. Electromagnetic waves in vacuum travel at the speed of light, c, so the relationship is lambda = c / f. Knowing the frequency lets you divide the speed of light by that frequency to get the wavelength. This speed is a constant for free space, coming from Maxwell’s equations, so the wavelength is fixed by c and f.

The impedance of free space is a ratio between electric and magnetic fields, not a factor that sets wavelength. The magnetic field amplitude or temperature don’t determine the wavelength in vacuum either.