Electromagnetic Spectrum
Interactive guide to light, radiation, and waves.
Select a band to filter
Radio Waves
Microwaves
Infrared (IR)
Visible Light
Ultraviolet (UV)
Ionizing RadiationX-Rays
Ionizing RadiationGamma Rays
Ionizing RadiationPhoton Calculator
Equations Used
E = h · fc = f · λh = Planck's Constant
c = Speed of Light
More Than Meets the Eye
The light we see with our eyes—the rainbow of colors from red to violet—is just a tiny fraction of reality. The universe is flooded with invisible light, from the giant Radio waves that carry our music to the deadly Gamma rays born in exploding stars. This entire range is called the **Electromagnetic (EM) Spectrum**.
Wavelengths
Think of these like ocean waves. Radio waves are kilometers long, gently rolling hills. Gamma rays are smaller than an atom, jagged and sharp. The shorter the wavelength, the more "punch" (energy) the wave packs.
Ionizing Power
Not all radiation is scary. "Non-ionizing" waves (Radio, Microwave, Light) can only heat things up. "Ionizing" waves (UV, X-Ray, Gamma) are like subatomic bullets—they can smash through DNA, causing mutations.
The Universal Speed Limit
One of the most amazing facts about physics is that all these waves—whether it's a radio signal or an X-ray—travel at exactly the same speed in a vacuum: **299,792,458 meters per second**.
Speed (c) equals Frequency (f) times Wavelength (λ). Because 'c' is constant, if frequency goes UP, wavelength MUST go down.
Visible Light Breakdown
When white light hits a prism, it splits into these colors because each wavelength bends at a slightly different angle.
Frequently Asked Questions
What is the relationship between Wavelength and Frequency?
They are inversely proportional. As wavelength gets shorter, frequency gets higher. The product of the two is always the speed of light ($c = f\lambda$). This means high-frequency waves (like X-rays) have tiny wavelengths.
Which electromagnetic waves are dangerous?
High-energy waves known as "Ionizing Radiation" are dangerous. This includes Ultraviolet (UV), X-Rays, and Gamma Rays. They have enough energy to strip electrons from atoms, causing DNA damage and cancer. Radio, Microwave, and Visible light are generally safe.
How do we calculate Photon Energy?
Photon energy is calculated using the Planck-Einstein relation: $E = hf$, where $h$ is Planck's constant and $f$ is frequency. Alternatively, $E = hc/\lambda$. This shows that energy increases directly with frequency.
Why can radio waves pass through walls but light cannot?
It depends on the wavelength relative to the material structure. Radio waves have long wavelengths that can easily pass through non-conductive materials like wood and drywall. Visible light has a tiny wavelength that interacts with the electrons in the wall, getting absorbed or reflected.
What is the visible light spectrum range?
Visible light ranges from approximately 400 nanometers (Violet) to 700 nanometers (Red). This is the only part of the spectrum that biological human eyes can detect.
Do microwaves remain in food?
No. Microwaves are waves of energy, not particles of matter. When the oven turns off, the waves disappear instantly, just like light when you switch off a bulb. They do not "contaminate" the food.
What produces Gamma Rays?
Gamma rays are produced by the most violent events in the universe, such as supernova explosions, neutron star collisions, and the decay of radioactive atomic nuclei.
Why is UV light used for sterilization?
UV-C light (short wavelength UV) is energetic enough to break the molecular bonds in DNA and RNA. This prevents bacteria and viruses from replicating, effectively killing them.
How fast do X-rays travel?
Like all electromagnetic radiation, X-rays travel at the speed of light ($c \approx 300,000$ km/s) in a vacuum.
Can humans see Infrared?
No, human eyes are not sensitive to Infrared. However, we can feel it as heat on our skin. Thermal imaging cameras can detect this heat and convert it into a visible image.