A Frequency of Light Calculator is a scientific tool that determines the frequency of a light wave based on its wavelength. Frequency, measured in Hertz (Hz), represents the number of wave crests that pass a point in space every second. Wavelength, on the other hand, is the distance between two consecutive crests. These two properties are inversely related through a fundamental constant: the speed of light. This calculator uses this relationship to find the frequency when the wavelength is known. This is a crucial calculation in many areas of science, including physics, chemistry, and astronomy, as the frequency of light is directly related to its energy and helps in identifying materials and analyzing celestial objects.
formula of Frequency of Light Calculator
The formula to calculate the frequency of light is derived from the universal wave equation, which states that the speed of a wave is equal to its frequency times its wavelength.
Frequency (f) = Speed of Light (c) / Wavelength (λ)
Where:
- f: The frequency of the light, which will be calculated in Hertz (Hz).
- c: The speed of light in a vacuum, which is a universal constant. Its value is approximately 299,792,458 meters per second (m/s).
- λ (lambda): The wavelength of the light. For the formula to work correctly, the wavelength must be in meters (m).
The Visible Light Spectrum: Wavelength and Frequency
This table shows the relationship between color, wavelength, and frequency for the visible portion of the electromagnetic spectrum. Notice that as the wavelength gets shorter, the frequency gets higher.
| Color | Wavelength Range (nanometers) | Corresponding Frequency Range (Terahertz) |
| Red | 620 - 750 nm | 400 - 484 THz |
| Orange | 590 - 620 nm | 484 - 508 THz |
| Yellow | 570 - 590 nm | 508 - 526 THz |
| Green | 495 - 570 nm | 526 - 606 THz |
| Blue | 450 - 495 nm | 606 - 668 THz |
| Violet | 380 - 450 nm | 668 - 789 THz |
Example of Frequency of Light Calculator
Let's calculate the frequency of green light that has a wavelength of 532 nanometers (nm).
Step 1: Convert the wavelength to the standard unit of meters.
The formula requires the wavelength to be in meters. Since 1 nanometer = 1 × 10⁻⁹ meters, we convert the value.
Wavelength (λ) = 532 nm = 532 × 10⁻⁹ meters.
Step 2: Apply the frequency formula.
Frequency (f) = Speed of Light (c) / Wavelength (λ)
Frequency (f) = 299,792,458 m/s / (532 × 10⁻⁹ m) ≈ 5.635 × 10¹⁴ Hz
This very large number is often expressed in a more convenient unit, Terahertz (THz), where 1 THz = 10¹² Hz.
Frequency (f) ≈ 563.5 THz
Therefore, the frequency of 532 nm green light is approximately 563.5 Terahertz.
Most Common FAQs
The frequency of light is directly proportional to its energy. This means that as the frequency increases, the energy of the light also increases. This relationship is described by the Planck-Einstein relation, E = hf, where 'E' is energy, 'h' is Planck's constant, and 'f' is the frequency. This is why high-frequency ultraviolet (UV) light has enough energy to cause a sunburn, while lower-frequency radio waves do not.
The speed of light constant (c) is given in units of meters per second. For the units to cancel out correctly in the formula and leave a result in Hertz (which is cycles per second), the wavelength must also be in meters. Using other units for wavelength, like nanometers, without converting first will produce an incorrect answer.
No, the frequency of a light wave remains constant regardless of the medium it travels through. What changes is the speed of the light and its wavelength. When light enters a denser medium, it slows down, and its wavelength becomes shorter, but the frequency (the number of waves passing a point per second) stays the same.