Question 1

What is wavelength?

Accepted Answer

Wavelength (λ) is the spatial distance between two consecutive identical points on a wave, such as crest to crest or trough to trough. It is measured in meters and is inversely proportional to frequency: higher frequency means shorter wavelength, and vice versa.

Question 2

Why does wave speed matter for wavelength?

Accepted Answer

The same frequency produces different wavelengths in different media because waves travel at different speeds. For example, a 440 Hz sound wave has a wavelength of about 0.78 m in air (343 m/s) but about 3.36 m in water (1,480 m/s). The relationship λ = v/f captures this dependency.

Question 3

What is the wavelength of visible light?

Accepted Answer

Visible light has wavelengths between approximately 380 nm (violet) and 700 nm (red). Using λ = c/f where c = 3×10⁸ m/s, red light at 430 THz has a wavelength of about 700 nm, while violet light at 790 THz has a wavelength of about 380 nm.

Question 4

What is the relationship between wavelength and energy?

Accepted Answer

For electromagnetic waves, energy is inversely proportional to wavelength: E = hc/λ, where h is Planck's constant. Shorter wavelengths (like X-rays and gamma rays) carry more energy per photon than longer wavelengths (like radio waves). This is why ultraviolet light can cause sunburn but visible light generally cannot.

Wavelength Calculator (λ = v/f)

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