Light, a form of electromagnetic radiation, possesses both wave-like and particle-like properties. One of its key characteristics is frequency, which describes the number of oscillations or cycles a wave completes in a unit of time. Understanding how to calculate the frequency of light is an essential skill for any student of physics, as it is integral to various scientific calculations and problem-solving.

In this article, we will discuss the basics of light, delve into the importance of frequency, and illustrate how to calculate the frequency of light using a simple formula.

1. The Nature of Light:

Light is an electromagnetic wave that travels in transverse waves. Transverse waves are characterized by oscillations that occur perpendicular to the direction in which they propagate. Electromagnetic waves consist of oscillating electric (E) and magnetic (B) fields oriented perpendicular to each other and to the direction in which the wave travels.

2. The Speed of Light:

The speed at which light travels plays a crucial role in calculating its frequency. In vacuum conditions, light travels at a constant speed denoted by ‘c,’ approximately equal to 299,792 kilometers per second (km/s) or 186,282 miles per second (mi/s). It should be noted that the speed may change when it passes through different media due to factors such as refractive index and dispersion.

3. Wavelength and Frequency:

Wavelength (λ), expressed in meters (m), signifies the spatial distance between two consecutive peaks or troughs in a wave. These peaks are known as crests, while troughs are called valleys. In contrast, frequency (ν) represents the number of oscillations made by a wave each second and is measured in Hertz (Hz). There exists an inverse relationship between wavelength and frequency when considering light.

4. The Formula for Calculating Frequency:

The relation between frequency, wavelength, and the speed of light is expressed in the formula:

ν = c / λ

Where:

ν = frequency (Hz)

c = speed of light (m/s or km/s)

λ = wavelength (m or km)

5. Calculation Example:

Let’s suppose that we have a light wave with a wavelength of 650 nanometers (nm), and we intend to find its frequency. Since one nanometer is equal to 1 x 10^(-9)m, we shall convert 650 nm to meters:

650 nm = 650 x 10^(-9) m = 6.5 x 10^(-7) m

Now, using the formula ν = c / λ:

ν = (3 x 10^8 m/s) / (6.5 x 10^(-7) m)

ν ≈ 4.62 x 10^(14) Hz

Therefore, the frequency of light with a wavelength of 650 nm is approximately equal to 4.62 x 10^(14) Hz.

Conclusion:

The ability to calculate the frequency of light is pivotal in numerous scientific contexts, including spectroscopy, astronomy, and telecommunications. By understanding the fundamental concepts of light waves and their behavior in different media, you can use the formula ν=c/λ to evaluate a wide variety of practical problems in science and engineering disciplines.