Wave & Frequency Visualiser — Interactive Physics Tool

What is Frequency?

Frequency is the number of complete wave cycles that occur in one second. It tells us how fast a wave oscillates or vibrates.

Think of it like a jump rope: If you swing it faster, more waves travel down the rope each second. That's higher frequency!

Units of Measurement

Hertz (Hz) is the standard unit for frequency:

• 1 Hz = 1 cycle per second
• 1 kHz (kilohertz) = 1,000 cycles per second
• 1 MHz (megahertz) = 1,000,000 cycles per second
• 1 GHz (gigahertz) = 1,000,000,000 cycles per second

Real-World Examples

• Sound Pitch: A bass note at 100 Hz vs. a high note at 1000 Hz - higher frequency = higher pitch
• AC Electricity: 60 Hz in USA, 50 Hz in Europe (60 or 50 complete cycles every second)
• Radio Stations: FM 100.1 MHz = 100,100,000 waves per second!
• Your WiFi: 2.4 GHz or 5 GHz (billions of waves per second)
• Visible Light: Red ~430 THz, Violet ~750 THz (trillion cycles per second!)

Key Relationships

• Higher frequency → Shorter wavelength (more waves packed in the same space)
• Higher frequency → More energy (why UV light can burn skin but radio waves can't)
• Frequency × Wavelength = Wave Speed (in the same medium, this is constant)

What is Amplitude?

Amplitude is the maximum displacement of a wave from its rest position (equilibrium). It measures how "tall" or "strong" the wave is.

Imagine a rope lying flat - when you shake it, amplitude is how high the wave peaks rise above (and how low the troughs fall below) the rope's resting position.

How It's Measured

Amplitude is measured from the center line (equilibrium) to the peak (or trough). NOT from peak to trough!

• Sound waves: Measured in decibels (dB) - relates to air pressure variation
• Light waves: Relates to brightness/intensity
• Electrical signals: Measured in Volts (V) or millivolts (mV)
• Water waves: Measured in meters or feet (wave height)

Real-World Examples

• Sound Volume: Whisper (low amplitude) vs. Rock concert (high amplitude) - same frequency, different loudness!
• Light Brightness: Dim LED (low amplitude) vs. Bright searchlight (high amplitude)
• Earthquakes: Small tremor vs. Major quake - both seismic waves, different amplitudes
• Radio Signals: Weak signal far from tower vs. Strong signal nearby
• Ocean Waves: Calm ripples (inches) vs. Tsunami (tens of meters)

Energy and Amplitude

Critical concept: Energy is proportional to amplitude SQUARED!

• Double the amplitude = 4× the energy
• Triple the amplitude = 9× the energy
• This is why powerful waves (high amplitude) can do so much more damage

Important Notes

• Amplitude does NOT affect frequency - you can have high amplitude at any frequency
• Amplitude does NOT affect wave speed (in the same medium)
• Amplitude DOES affect how much energy the wave carries
• In electronics, controlling amplitude is how we control power delivery

What is Wavelength?

Wavelength (symbol: λ, pronounced "lambda") is the distance between two identical points on consecutive waves. It's the physical length of one complete wave cycle.

Think of ocean waves: it's the distance from one wave crest to the next crest (or trough to trough).

How to Identify Wavelength

You can measure wavelength between any two corresponding points:

• Crest to crest (peak to peak)
• Trough to trough (valley to valley)
• Any point to the same point on the next wave
• Important: Must measure to the SAME phase on the next cycle!

Real-World Examples

• AM Radio: ~200 meters wavelength (long waves travel far!)
• FM Radio: ~3 meters wavelength
• WiFi (2.4 GHz): ~12.5 cm wavelength
• Microwave oven: ~12 cm wavelength (sized to match food molecules!)
• Visible Red Light: ~700 nanometers (0.0000007 meters!)
• Visible Violet Light: ~400 nanometers
• Ocean waves: Can be 100+ meters between crests

The Inverse Relationship

Key Concept: Frequency and wavelength are inversely proportional (when wave speed is constant)

• Higher frequency → Shorter wavelength
• Lower frequency → Longer wavelength
• If you double the frequency, you halve the wavelength
• This is why bass sounds (low freq) have long wavelengths and can "travel through walls"

Why Wavelength Matters

• Antenna Design: Antennas are often 1/4 or 1/2 wavelength for optimal reception
• Diffraction: Waves can bend around objects smaller than their wavelength
• Interference: Waves combine constructively or destructively based on wavelength alignment
• Resolution: Shorter wavelengths can resolve finer details (why electron microscopes beat optical ones)

All EM Waves in Vacuum

All electromagnetic waves travel at the speed of light in a vacuum: c = 3 × 10⁸ m/s

This means for EM waves: λ = c/f

• Radio wave (1 MHz): λ = 300 meters
• Microwave (10 GHz): λ = 3 cm
• Visible light (600 THz): λ = 500 nm
• X-ray (30 PHz): λ = 10 nm