Wavelength & Frequency Calculator
Enter wave speed and frequency (or wavelength) to find the other. λ = v/f. Speed of light 3e8 m/s, f=100 MHz → λ=3 m; audible 20 Hz–20 kHz maps to 17 mm–17 m.
Input Data
Results
At a glance:The wave relation λ = v/f connects wavelength λ (m), wave speed v (m/s) and frequency f (Hz). Wavelength λ is the distance between successive crests; frequency f is the number of oscillations per second; wave speed v is how fast a crest travels. The three satisfy λ = v/f, equivalently v = f·λ. Frequency is set by the source and stays fixed when the wave changes medium; wavelength changes with the medium's speed. Example: light c=3e8 m/s at f=100 MHz → λ=3 m; audible 20 Hz–20 kHz → λ from 17 mm to 17 m (low notes have long wavelength). Common wave speeds: light in vacuum c=299,792,458 m/s; sound in air ≈343 (varies with air temperature); sound in water ≈1480; on a string v=√(T/μ). Applications: (1) radio and antenna design — antenna length ≈ λ/4 or λ/2; (2) musical instruments — wavelength sets pitch and pipe length; (3) optical fibre and laser — wavelength sets colour and dispersion; (4) medical ultrasound — wavelength sets resolution; (5) DSE Physics wave questions.
Formula
Wave relation: λ = v / f
Speed: v = f·λ
Frequency: f = v / λ
Light: c = 3×10⁸ m/s; sound in air ≈343 m/s
$$\lambda = \frac{v}{f}, \quad v = f\lambda$$How to Use
- Enter wave speed v (m/s; light 3e8, air sound 343).
- Enter frequency f (Hz) or wavelength λ (m).
- The tool computes the third quantity.
Case Studies
FM radio wavelength
Speed of light c=3e8 m/s, frequency f=100 MHz=1e8 Hz.
λ = c/f = 3e8/1e8 = 3 m.
A quarter-wave antenna is about 0.75 m long.
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.