What is Wave Frequency? Easy Explanation for Students

📚 What is Wave Frequency?

Wave frequency is all about how often a wave repeats itself in a certain amount of time. Think of it like this: imagine you're on a beach, and you're counting how many waves crash onto the shore every minute. That's kind of like measuring wave frequency!

In physics, we define wave frequency more precisely. It's the number of complete cycles (or oscillations) of a wave that pass a given point per unit of time. The standard unit for frequency is Hertz (Hz), which is equal to one cycle per second.

📐 Understanding the Formula

The relationship between frequency ($f$), wave speed ($v$), and wavelength ($\lambda$) is given by the formula:

$v = f \lambda$

Where:

• 🌊 $v$ is the wave speed (how fast the wave is traveling).
• ⏱️ $f$ is the frequency (how many cycles per second).
• 📏 $\lambda$ is the wavelength (the distance between two corresponding points on the wave, like crest to crest).

From this formula, we can find frequency if we know the wave speed and wavelength:

$f = \frac{v}{\lambda}$

📊 Key Factors Affecting Wave Frequency

• 🧮 Wave Speed: Higher wave speed means higher frequency, assuming wavelength stays constant.
• 📏 Wavelength: Shorter wavelength means higher frequency, assuming wave speed stays constant.
• 🌱 Medium: The medium through which a wave travels can affect its speed and, therefore, its frequency. For example, sound waves travel at different speeds in air, water, and solids.

💡 Quick Tips

• 🎧 Audible Range: Humans can typically hear sound waves with frequencies between 20 Hz and 20,000 Hz.
• 🌈 Light and Color: Different colors of light correspond to different frequencies. For instance, blue light has a higher frequency than red light.
• 📱 Radio Waves: Radio stations broadcast at specific frequencies, which is how your radio can tune into different stations.

✏️ Practice Quiz

1. A wave has a speed of 10 m/s and a wavelength of 2 meters. What is its frequency?
2. What happens to the frequency of a wave if the wavelength is doubled but the speed remains constant?
3. Sound travels faster in water than in air. How does this affect the frequency of a sound wave as it moves from air to water, assuming the wavelength remains constant?

Answers:

1. $f = \frac{10 \text{ m/s}}{2 \text{ m}} = 5 \text{ Hz}$
2. The frequency is halved ($f = \frac{v}{2\lambda}$).
3. Since $v = f \lambda$, if the speed ($v$) increases and the wavelength ($\lambda$) remains constant, the frequency ($f$) must increase.