Applications of Electromagnetic Radiation

Core Concepts

Just because you can’t see something does not mean it isn’t there, hard at work! Many things that we cannot see in our lives play a crucial role in keeping them running smoothly. One of the most intriguing and fundamental aspects of this invisible realm is the electromagnetic spectrum. This spectrum encompasses a vast range of electromagnetic waves, each with distinct properties and applications that impact our daily lives in ways we might not even be aware of. From the static on the radio we hear to the super-powered gamma rays, the electromagnetic spectrum plays a crucial role in modern technology, communication, medicine, and scientific exploration.

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What is the Electromagnetic Spectrum?

A depiction of the EM spectrum going from the least to most energetic groups of radiation

The electromagnetic (EM) spectrum is a continuum of energy that includes a wide array of electromagnetic waves, each with a specific wavelength and frequency. Wavelength refers to the distance between successive wave crests, while frequency represents the number of wave cycles that pass a given point in a unit of time. A high frequency paired with a low wavelength means higher energy (such as gamma waves), the opposite is the case for a group with a low frequency and a higher wavelength (such as radio waves)  The spectrum is divided into different regions based on these wavelength and frequency characteristics, and each region has unique properties and applications

Electromagnetic Spectrum: Radio Waves


Radio waves are the longest and weakest type of radiation present on the EM spectrum. Being measured with a distance of ~102 m, there are a lot of applications in the everyday world that would be useless without radio waves!


  • Radio waves are extensively used for wireless communication. This includes radio broadcasting, television broadcasting, cellular networks, Wi-Fi, Bluetooth, and satellite communication. They enable long-range communication without the need for physical connections.
  • GPS also relies on radio signals transmitted by satellites to determine the precise location of receivers on Earth. This technology is used for navigation in vehicles, smartphones, aviation, and more.
  • Radio waves can be used for wireless power transmission. While this technology is still relatively new, it has the potential to charge electronic devices and even power remote sensors without physical connections

Electromagnetic Spectrum: Microwaves


Microwaves are the next category of radiation on the EM spectrum, with a wavelength of ~10-2 m. Even though they have one universally known use, you’d be surprised at what else they are used in!


  • The most familiar application of microwaves is in microwave ovens, which use microwaves to heat and cook food by exciting water molecules within the food to start heating it up.
  • Microwaves are also crucial components of radar systems. Radar uses microwaves to detect and locate objects by sending out microwave signals and analyzing the reflections. This technology is used in weather radar, air traffic control, military surveillance, and autonomous vehicles for object detection.
  • Believe it or not, Wi-Fi technology operates in the microwave frequency range to provide wireless internet connectivity. Devices like routers use microwaves to transmit data wirelessly to connected devices.

Electromagnetic Spectrum: Infrared


Infrared is the next section, just between microwaves and the light we can actually see. Measured with a wavelength of ~10-4 m , infrared has a unique ability to sense heat. Objects, including our own bodies, emit heat in the form of infrared radiation. This property of infrared radiation makes it a valuable tool in various applications.


  • Infrared waves are used in thermal imaging cameras to create images based on the heat emitted by objects. This technology is used in various fields, including firefighting, search and rescue operations, building inspections, and military applications. It can help locate people or objects in low-light or obscured environments by detecting their heat signatures.
  • Many household electronics, such as televisions, air conditioners, and DVD players, use infrared remote controls to transmit signals that control their functions. These remote controls work by sending coded infrared signals that the devices can interpret and respond to.
  • Infrared cameras can also be used to detect and track gas leaks in industrial settings, as many gases emit infrared radiation. This technology is valuable for safety inspections in factories, refineries, and chemical plants.

Electromagnetic Spectrum: Visible Light

visible light electromagnetic spectrum
The small visible portion of the EM spectrum

After infrared, the next section of the EM spectrum is the only ones humans can actually visually interpret! While this may account for all of the vivid colors in our lives, it only covers a fraction of the entire EM spectrum, measured with wavelengths near ~10-7 m. The color red is at the weaker end, whilst violet is considered the strongest of the visible light colors.


  • Visible light is the section of the EM spectrum that plants utilize for photosynthesis, the process through which they convert light energy into chemical energy to fuel their growth. This foundational process supports the entire food chain and is vital for Earth’s ecosystems.
  • Visible light is also used to induce fluorescence in certain substances, making them emit light of a different color. This technique helps researchers track and study specific molecules and processes at the cellular level.
  • Interestingly enough, bioluminescent organisms, such as fireflies and some marine creatures, emit visible light as a natural phenomenon. Scientists study these organisms to gain insights into genetics, chemistry, and the potential applications of bioluminescence in fields like medicine and environmental monitoring.

Electromagnetic Spectrum: Ultraviolet (UV) Light

uv light electromagnetic spectrum
A scorpion having its picture taken within a UV light

Ultraviolet (UV) light is a form of EM radiation that lies just beyond the violet end of the visible light spectrum. With a wavelength of ~10-8 m, UV light has unique properties that make it both beneficial and potentially harmful. It plays a significant role in various real-life applications, contributing to fields ranging from health and technology to scientific research.


  • UV light has shown germicidal properties that can effectively deactivate bacteria, viruses, and other microorganisms. UV sterilization is used in water treatment plants, hospitals, laboratories, and even air purifiers to reduce the spread of infectious diseases.
  • Many countries use UV-sensitive inks and features on banknotes and official documents. These features are invisible under regular light but become visible and distinct under UV light, making counterfeiting more difficult.
  • UV light can reveal even hidden layers and details in artwork and historical artifacts, aiding in restoration efforts and providing insights into artistic techniques and materials.

Electromagnetic Spectrum: X-Rays

x rays electromagnetic spectrum

X-rays occupy are characterized by their ability to penetrate matter. With wavelengths shorter than UV light (beginning at ~10-10 m), X-rays hold a potent energy that unveils hidden worlds. Their unique capacity to expose what lies beyond ordinary sight beckons us to explore the depths of the unseen, not just at the doctor’s office


  • X-ray diffraction is a laboratory technique that reveals the atomic structure of materials. It’s used to determine the arrangement of atoms in crystals and is essential for understanding the properties of various materials.
  • X-rays can also be employed for non-destructive testing of materials in industries like manufacturing and construction. Engineers use X-rays to inspect welds, check the integrity of pipelines, and ensure the quality of manufactured products.
  • Paleontologists use X-ray imaging to examine fossils without the need for physical excavation or destructive sampling. This allows researchers to study the internal structures of fossils, revealing details that might otherwise be hidden.

Electromagnetic Spectrum: Gamma Rays

gamma rays electromagnetic spectrum

With a wavelength similar to the size of some atoms (starting at ~10-12 m), gamma rays are the most powerful form of energy on the EM spectrum. Although they are well-known for either causing superpowers or super tumors, gamma rays play a lot more roles in the medical and industrial worlds than they do in show business!


  • One of the most well-known applications, Gamma rays are used in radiation therapy to treat cancer. Highly focused gamma radiation targets cancerous cells, damaging their DNA and inhibiting their ability to replicate. This treatment approach helps shrink tumors and eliminate cancer cells while minimizing damage to surrounding healthy tissue.
  • In industries like steel manufacturing, gamma ray gauges are used to measure the thickness of materials as they move along a production line, ensuring quality control.
  • In industrial and medical contexts, gamma rays are employed to sterilize and preserve medical equipment, food, and other products. Their high-energy nature effectively kills bacteria, viruses, and other microorganisms, ensuring safety and preventing contamination.