The energy travelling through space is termed radiation. Sunshine is one of the common forms of radiation that delivers heat, sunshine, and light. While we enjoy and depend on it, we also control our exposure to it. This is because prolonged exposure to certain radiations can lead to health problems that can eventually lead to death. Beyond ultraviolet radiation, higher-energy radiation exists, and they are used in medicine. We get these radiations in low doses from space, air, earth, and rocks. In this article, let us discuss the different types of radiation.
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Types of Radiation
As we know, radiation is energy emitted by a source and then travels through a medium, such as air, until it is absorbed by matter. Based on the energy of the radiated particles, they are classified as follows:
- Ionising radiation
- Non-ionising radiation
Ionising Radiation
Ionising radiation is radiation with sufficient energy that produces ions in matter at the molecular level upon the interaction. In other words, it can remove tightly bound electrons from the orbit of an atom, causing the atom to become charged or ionised. If the interacting matter is a human body, it can result in significant damage, including damage to DNA and the denaturation of proteins. This is not to say that non-ionising radiation can’t cause injury to humans, but the injury is generally limited to thermal damage, i.e. burns. One of the most interesting things is that the visible spectrum is essentially the divide between ionising and non-ionising radiation. This makes sense clinically when we think of UV radiation causing skin cancer.
Types of Ionising Radiation
Ionising radiation is caused due to unstable atoms that either have excess energy, mass, or both. To return to a stable state, they have to release the extra mass or energy in the form of radiation. Given below are the different types of ionising radiation, along with a few of their characteristics:
- Alpha particles
- Beta particles
- Gamma rays
- X-rays
Alpha Particles
The particles consisting of two protons and two neutrons bound together are known as alpha particles. These particles are identical to the helium atom and are emitted during radioactive decay and are known as alpha decay.
Uses of Alpha Particles
- They are used as smoke detectors. When the smoke enters the detector, the number of alpha particles reduces and gets detected by the alarm. Americium-241 is an example of a smoke detector
- They are used as static eliminators to remove the static charges from the equipment. Polonium-210 is an example of a static eliminator.
Beta particles
Particles with high-energy electrons or positrons are known as beta particles. These are ejected during the radioactive decay and are known as beta decay.
Uses of Beta Particles
- Strontium-90 is used for the treatment of bone cancer
- For emergency lightning, tritium is used.
Gamma Rays
During radioactive decay, the nucleus emits a packet of electromagnetic energy, known as a gamma-ray. In the electromagnetic spectrum, gamma photons are the most energetic photons.
Uses of Gamma Rays
- Cobalt-60 is used for sterilisation of medical equipment and pasteurisation of food.
- Caesium-137 is used to measure soil moisture density and control the flow of liquids in industries.
X-Rays
X-ray is a packet of a photon that is produced by electrons that are external to the nucleus. They originate from the electron cloud of an atom.
Properties of X-rays
| Physical | They are invisible to the eyes but have the property of attenuation, absorption and scattering |
| Chemical | They produce highly active radical of OH ions that can bring chemical changes in the solution |
| Biological | They are used for cancer treatment and may cause genetic changes |
| Physiochemical | They are used for producing photographic films |
Uses of X-rays
- X-rays are used for crystallography and fluoroscopy to control the quality of materials.
- X-rays are used to detect tumours and infections.
Overview of Ionising Radiation
| Properties of Ionising Radiation | |||
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Non – Ionising Radiation
Non-ionizing radiation is the term given to radiation that has insufficient energy to cause ionisation. These kinds of radiation contradict ionising radiation like x-rays, gamma rays, and alpha particles, which are on the other end of the spectrum and are unstable and reactive. Non-ionizing radiation can produce heat, which is how food is cooked in a microwave oven. Humans and other organisms can see some types of non-ionizing radiation, such as visible light and infrared light.
Following are the types of non-ionising radiation:
- Ultraviolet radiation
- Visible light
- Infrared
- Microwave
- Radio waves
- Very Low Frequency (VLF)
- Extremely Low Frequency (ELF)
- Thermal radiation
- Black-body radiation
Ultraviolet Radiation
Sunlight is the main source of ultraviolet (UV) radiation. Prolonged exposure of skin to this radiation leads to skin cancers. Sun lamps and tanning beds also emit UV rays. It has a wavelength of 400 nm.
Types of UV radiation
Following are the types of UV radiation:
- UVA
- UVB
- UVC
Uses of Ultraviolet Rays
- UV radiation is widely used in industrial processes and in medical and dental practices for various purposes, such as killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy and suntanning.
Visible Light
Visible light is defined as the electromagnetic spectrum that is visible to the human eye. When the full spectrum passes through the prism, the spectrum separates depending on its wavelength into the colours of the rainbow. The shortest wavelength (380 nm) is of violet, and the longest wavelength (700 nm) is red.
Uses of Visible Light
- Visible light used in fibre optic communications, photography, and electronic devices.
Infrared Radiation
Infrared radiation (IR) is also known as infrared, with a wavelength range of 700 nm to 1 mm. These are longer than visible light. Near wavelength, mid-wavelength, long-wavelength and far-infrared are the different categories of infrared.
Uses of infrared waves
Following are the uses of infrared waves:
- Thermography is a method to determine the relative temperature of the object, and for this, infrared waves are used.
- Infrared waves are invisible but can be sensed as they conduct heat. Because of this property, infrared waves are used in physical therapy for heating purposes.
Microwaves
Microwaves are waves with different wavelengths and frequencies. They have a wavelength of 30 cm to 1 mm and frequency between 300 MHz and 300 GHz.
Uses of Microwaves
- They are used in communications, radio astronomy, remote sensing, radar, and of course, owing to their heating application, they are used in cooking as well.
Radio waves
Radio waves are electromagnetic radiation that has a wavelength longer than infrared and travel at the speed of light. The propagation characteristics of the radio waves have different frequencies, like long waves to cover the earth and short waves that get reflected off in the ionosphere.
Uses of radio waves
Following are the uses of radio waves:
- Radio waves are used for mobile radio communication.
- Radar and satellite communication.
- For navigation systems.
Following are the links for other types of non-ionising radiation:
| Black Body Radiation: Wien Displacement Law |
| Heat Transfer: Thermal Radiation |
Frequently Asked Questions – FAQs
What is Radiation?
What are Gamma Rays?
X-Rays are invisible to eyes but have the property of attenuation, absorption and scattering.
1. True
2. False
What is ultraviolet radiation?
What are microwaves?
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