Wavelength Calculator

Wavelength Calculator – Calculate Wavelength, Frequency & Energy Online

Free wavelength calculator to find wavelength from frequency, calculate wave speed, and convert between wavelength units. Includes formulas, examples, and step-by-step solutions.

Wavelength Calculator

Calculate Wavelength, Frequency & Wave Energy Instantly

Calculate Wavelength

What is Wavelength?

Wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is typically measured in meters (m) or its subunits like nanometers (nm) for light.

Key Characteristics of Wavelength

  • Symbol: Represented by the Greek letter lambda (λ)
  • SI Unit: Meter (m), also nm, μm, mm, cm depending on wave type
  • Inverse Relationship: Inversely proportional to frequency (higher frequency = shorter wavelength)
  • Wave Speed: Related by equation v = λf (velocity = wavelength × frequency)
  • Energy Relation: For photons, shorter wavelength means higher energy
  • Medium Dependent: Changes when wave enters different medium (frequency stays constant)

Wavelength in Different Wave Types

Electromagnetic Waves (Light)

Travel at speed of light c = 3×10⁸ m/s in vacuum. Range from radio waves (km) to gamma rays (pm). Visible light: 380-700 nm.

Sound Waves

Mechanical waves through medium. Speed ~343 m/s in air. Audible range: 17 mm to 17 m (20 Hz to 20 kHz).

Water Waves

Surface waves on water. Speed depends on depth and wavelength. Ocean waves: meters to hundreds of meters.

Wavelength Formulas & Equations

The fundamental relationship between wavelength, frequency, and wave speed is expressed through several equivalent formulas. These equations are essential for understanding wave behavior.

Primary Wavelength Formulas

Wavelength Formula

Formula:

λ = v / f

Where λ is wavelength, v is wave velocity, and f is frequency

Light Wavelength

Formula:

λ = c / f

For electromagnetic waves where c = 3×10⁸ m/s (speed of light)

Wave Equation

Formula:

v = λf

Fundamental wave equation showing relationship between all three quantities

Frequency Formula

Formula:

f = v / λ

Find frequency when wavelength and velocity are known

Energy-Wavelength Relationship

Photon Energy Formula

E = hf = hc / λ

Where: E is energy (Joules), h is Planck's constant (6.626×10⁻³⁴ J·s), c is speed of light, f is frequency, λ is wavelength

Key Insight: Shorter wavelengths have higher energy. This is why ultraviolet light (short λ) is more energetic and potentially harmful than infrared light (long λ).

Detailed Example: Calculate Wavelength

Find the wavelength of light with frequency 5×10¹⁴ Hz:

Given Information:

  • Frequency (f) = 5×10¹⁴ Hz
  • Speed of light (c) = 3×10⁸ m/s
  • Need to find: Wavelength (λ)

Solution Steps:

Step 1: Use wavelength formula for light

λ = c / f

Step 2: Substitute values

λ = (3×10⁸) / (5×10¹⁴)

Step 3: Calculate

λ = 6×10⁻⁷ m = 600 nm

Result: The wavelength is 600 nm, which corresponds to orange light in the visible spectrum. This demonstrates the inverse relationship: high frequency results in short wavelength.

Electromagnetic Spectrum Wavelengths

The electromagnetic spectrum encompasses all types of electromagnetic radiation, categorized by wavelength and frequency. Each region has distinct properties and applications.

Wavelength Ranges by Type

Type Wavelength Range Frequency Range Applications
Radio Waves > 1 mm < 300 GHz Broadcasting, Communication
Microwaves 1 mm - 1 m 300 MHz - 300 GHz Radar, Cooking, WiFi
Infrared 700 nm - 1 mm 300 GHz - 430 THz Thermal imaging, Remote
Visible Light 380 - 700 nm 430 - 790 THz Human Vision, Photography
Ultraviolet 10 - 380 nm 790 THz - 30 PHz Sterilization, Tanning
X-rays 0.01 - 10 nm 30 PHz - 30 EHz Medical Imaging, Security
Gamma Rays < 0.01 nm > 30 EHz Cancer Treatment, Astronomy

Frequently Asked Questions

What is wavelength?

Wavelength is the distance between consecutive corresponding points of the same phase on a wave, such as two adjacent peaks or troughs. It is measured in meters (m) or subunits like nanometers (nm) for light. The wavelength formula is λ = v/f, where λ is wavelength, v is wave velocity, and f is frequency. Wavelength determines many wave properties including color for visible light.

How do you calculate wavelength?

To calculate wavelength, use the formula λ = v/f where v is wave velocity and f is frequency. For light waves, use λ = c/f where c is the speed of light (3×10⁸ m/s). For example, light with frequency 5×10¹⁴ Hz has wavelength λ = (3×10⁸)/(5×10¹⁴) = 6×10⁻⁷ m = 600 nm. Always ensure units are consistent: velocity in m/s and frequency in Hz gives wavelength in meters.

What is the formula for wavelength?

The wavelength formula is λ = v/f, where λ (lambda) is wavelength in meters, v is wave velocity in m/s, and f is frequency in Hz. For electromagnetic waves, this becomes λ = c/f where c = 3×10⁸ m/s is the speed of light. The relationship can also be expressed as v = λf, showing that wavelength and frequency are inversely proportional when wave speed is constant.

What is the relationship between wavelength and frequency?

Wavelength and frequency have an inverse relationship: as wavelength increases, frequency decreases, and vice versa. This relationship is expressed by the equation v = λf where v is constant wave velocity. For light in vacuum, c = λf where c is the speed of light. Mathematically, λ = c/f shows that doubling frequency halves wavelength. High frequency waves (like X-rays) have short wavelengths, while low frequency waves (like radio) have long wavelengths.

How do you find frequency from wavelength?

To find frequency from wavelength, rearrange the wavelength formula to f = v/λ where f is frequency, v is wave velocity, and λ is wavelength. For light waves, use f = c/λ where c = 3×10⁸ m/s. For example, light with wavelength 500 nm (5×10⁻⁷ m) has frequency f = (3×10⁸)/(5×10⁻⁷) = 6×10¹⁴ Hz. Convert wavelength to meters first for correct calculation.

What is the wavelength of visible light?

Visible light wavelengths range from approximately 380 nm (violet) to 700 nm (red). Specific colors have characteristic wavelengths: violet (380-450 nm), blue (450-495 nm), green (495-570 nm), yellow (570-590 nm), orange (590-620 nm), and red (620-700 nm). The human eye is most sensitive to green light around 555 nm. Wavelengths outside this range (UV < 380 nm, IR > 700 nm) are invisible to humans.

How does wavelength affect energy?

For electromagnetic radiation, wavelength and energy have an inverse relationship expressed by E = hc/λ, where E is energy, h is Planck's constant (6.626×10⁻³⁴ J·s), c is the speed of light, and λ is wavelength. Shorter wavelengths carry more energy: gamma rays (very short λ) are extremely energetic, while radio waves (very long λ) have low energy. This is why UV light can cause sunburn while radio waves cannot.

Disclaimer: This wavelength calculator provides accurate results based on the formulas λ = v/f and c = λf using the speed of light c = 2.998×10⁸ m/s. Calculations assume waves travel through vacuum or air unless specified. For other media, wave velocity changes. Results are for educational and general physics calculations. For precise scientific work, consider refractive index, dispersion, and other medium-specific properties. Always verify critical calculations independently.