Frequency
Also known as: f, pitch
The number of complete wave cycles that pass a fixed point per second, measured in hertz (Hz). Determines the pitch of sound, the color of visible light, and the energy of photons.
💡 Intuition
How many times something vibrates per second—high frequency means very rapid vibration.
Core Idea
Frequency and period are reciprocals — doubling the frequency halves the period.
Formal View
🔬 Example
🎯 Why It Matters
Determines the pitch of sound, the color of visible light, and the energy of photons.
⚠️ Common Confusion
Hertz (Hz) means 'cycles per second'—it's a rate of repetition, not a total count.
💭 Hint When Stuck
When solving a frequency problem, check whether you are given the period or the wave speed and wavelength. If given the period T, use f = 1/T. If given speed v and wavelength \lambda, use f = v/\lambda. Always express your answer in hertz (Hz).
Related Concepts
Prerequisites
Next Steps
How Frequency Connects to Other Ideas
To understand frequency, you should first be comfortable with waves. Once you have a solid grasp of frequency, you can move on to wavelength and period.
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Frequently Asked Questions
What is Frequency in Physics?
The number of complete wave cycles that pass a fixed point per second, measured in hertz (Hz).
Why is Frequency important?
Determines the pitch of sound, the color of visible light, and the energy of photons.
What do students usually get wrong about Frequency?
Hertz (Hz) means 'cycles per second'—it's a rate of repetition, not a total count.
What should I learn before Frequency?
Before studying Frequency, you should understand: waves.
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