What is Meant by Radiation?
Radiation is the energy that travels from space to earth. Sun is the most abundant source of radiation. Although we enjoy the sunshine and its benefits, we are also exposed to the health hazards that can occur due to overexposure to certain selective radiations. For example, prolonged exposure to ultraviolet radiation can cause skin cancer and can even lead to death. Higher energy radiations are also used in medical treatments. Radiation travels in the form of electromagnetic waves and is also found in the form of highly energetic subatomic particles.Hence let's take a look at the different types of radiation in the section below.
Types of Radiation and Properties
Four types of radiation, which one generally comes across are - alpha radiation, beta radiation, gamma radiation and x radiation. Radiation travels through a medium after being emitted from a source and is finally absorbed by matter.
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Hence, all types of radiation can be broadly classified into ionizing and non-ionizing radiation.
Ionizing Radiation
Ionizing radiation has enough energy such that when it reacts with an atom present in the matter, it can easily remove the electrons which are tightly bound from the outer orbit of the atom, resulting in the charging or ionization of the atom. Higher frequency and shorter wavelength radiations have much more energy than the lower frequency and larger wavelength radiations. All electromagnetic radiations are not ionizing. X rays and gamma rays which are present in the higher frequency portion of the electromagnetic spectrum are ionizing. These radiations are generally harmful to the human body as it can damage DNA and cause denaturation of proteins.
Types of Ionizing Radiation
Unstable atoms characterize ionizing radiation. To regain stability, they release energy in the form of types of radiation as they typically contain excess energy or mass or both.
The primary three types of ionizing radiation include alpha rays, beta rays and gamma rays. X-rays are also a type of ionizing radiation.
Alpha Particles: These are emitted during radioactive decay and have two protons and two neutrons.
Beta Particles: These are electrons/positrons with high energy.
Gamma Rays: These are emitted from the nucleus during radioactive decay and are a packet of energetic photons.
X - Rays: Photons produced when external electrons hit the nucleus.
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Non-Ionizing Radiation
These rays do not cause ionization. They generally produce heat which is sometimes severe enough to cause burns. Some of the non-ionizing radiation is visible for the human eye, such as visible light and infrared radiation.
Non - Ionizing Radiation Examples
UV Rays: Sun, tanning beds are sources of UV Rays.
Visible Light: The shortest wavelength is that of the violet light, and the longest wavelength is for the red light.
Black body radiation.
Radio Waves and Microwaves: Radio waves have wavelengths larger than that of infrared rays which are useful for radar communication. Microwaves produce the right amount of heat for cooking food.
Very low-frequency radiation.
Infrared Radiation: They are used in emergency signals as they are distinctly visible.
Thermal radiation.
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Solved Examples
1. State the difference between ionizing and non-ionizing radiation.
Answer: ionizing radiation can cause ionization of ions at the molecular level switch can cause severe damage to human cells and even death. Non-ionizing radiation does not penetrate the bones but can cause massive burns. Ionizing radiation has shorter wavelength and higher frequency, therefore higher energy. While for non-ionizing radiation it's of longer wavelength and lower frequency, therefore lower energy.
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2. Give some examples of ionizing and non-ionizing radiation.
Answer: Alpha particles, Beta particles, Gamma rays, X-Rays are some examples of ionizing radiation. While ultraviolet rays, infrared radiation, microwaves, radio waves are some examples of non-ionizing radiation.
Fun Facts
Alpha particles are used in smoke detectors. The number of alpha particles reduces smoke, and the alarm rings.
Polonium 210 is a static eliminator that helps to remove static charges from a system.
Beta particles such as tritium are used for emergency lighting.
Gamma Rays are used for pasteurization of food, measuring the moisture density in the soil and sterilization of medical instruments.
X rays are used in the treatment of cancers and tumors.
Infrared waves can be used to measure the relative temperature of the object.
Radio waves are used in satellite communication and navigation systems.
FAQs on Types of Radiation
1. What is radiation and how is it broadly classified?
Radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. It is broadly classified into two main categories based on its energy:
- Ionizing radiation: High-energy radiation that can remove tightly bound electrons from atoms, creating ions. Examples include alpha particles, beta particles, gamma rays, and X-rays.
- Non-ionizing radiation: Lower-energy radiation that does not have enough energy to ionize atoms. Examples include visible light, infrared, microwaves, and radio waves.
2. What are the main types of ionizing radiation emitted during radioactive decay?
The three primary types of radiation emitted from an unstable atomic nucleus during radioactive decay are:
- Alpha (α) radiation: Consists of particles that are identical to a helium nucleus, containing two protons and two neutrons.
- Beta (β) radiation: Consists of high-energy electrons or positrons that are emitted from the nucleus during decay.
- Gamma (γ) radiation: Consists of high-energy photons, which are packets of electromagnetic energy, released to stabilise the nucleus after decay.
3. What is the key difference between ionizing and non-ionizing radiation?
The primary difference lies in their energy levels and their effect on matter. Ionizing radiation (like gamma rays and alpha particles) has sufficient energy to knock electrons out of atoms, a process which can damage the DNA in living cells. In contrast, non-ionizing radiation (like radio waves and visible light) has lower energy and cannot ionize atoms, though it can transfer energy in other ways, such as generating heat.
4. Can you provide some common examples of both ionizing and non-ionizing radiation?
Certainly. Here are some common examples for each category:
- Examples of Ionizing Radiation: Alpha particles from radioactive elements like uranium, Beta particles from carbon-14, Gamma rays used for medical sterilization, and X-rays used in medical diagnostics.
- Examples of Non-ionizing Radiation: Ultraviolet (UV) rays from the sun, visible light from a bulb, infrared radiation used in remote controls, microwaves in an oven, and radio waves for communication.
5. What are the fundamental properties of alpha, beta, and gamma radiation?
The fundamental properties of these three types of radiation differ significantly in terms of charge, mass, and penetrating ability:
- Alpha (α) Particles: Have a positive charge (+2e), a large mass, and move relatively slowly. They possess high ionizing power but very low penetrating power, being easily stopped by a sheet of paper.
- Beta (β) Particles: Have a negative charge (-e) and a very small mass. They have moderate ionizing power and moderate penetrating power, requiring a thin sheet of aluminium to be stopped.
- Gamma (γ) Rays: Have no charge and no mass. They travel at the speed of light. They have low ionizing power but extremely high penetrating power, requiring thick lead or concrete for shielding.
6. Why do alpha, beta, and gamma radiation have different penetrating powers?
The difference in penetrating power is a direct result of the radiation's mass, size, and electric charge, which determines how it interacts with matter. Alpha particles are large and highly charged, causing them to interact intensely with atoms and lose energy quickly over a short distance. Beta particles are much smaller and less charged, leading to fewer interactions and allowing them to travel further. Gamma rays, having no mass or charge, interact the least with matter, which allows them to pass through most materials easily, giving them the highest penetrating power.
7. How is radiation used in everyday applications, beyond medical imaging?
Radiation has several crucial non-medical applications. For example:
- Smoke Detectors: Many household smoke detectors use a small amount of Americium-241, an alpha emitter, to ionize air. Smoke particles disrupt this ionization, triggering the alarm.
- Food Preservation: Gamma radiation is used to irradiate foods like spices and vegetables to kill bacteria, mould, and pests, thereby extending shelf life without making the food radioactive.
- Archaeological Dating: Carbon-14, a beta emitter, is used in radiocarbon dating to determine the age of organic materials up to 50,000 years old.
8. What makes ionizing radiation, such as gamma rays, particularly hazardous to biological cells?
Ionizing radiation is hazardous primarily because its high energy can directly or indirectly damage the DNA within living cells. When radiation strikes a cell, it can break the chemical bonds in the DNA molecule or create free radicals that do so. This damage can lead to harmful mutations, cell death, or the kind of uncontrolled cell growth that results in cancer. Because gamma rays are highly penetrating, they can cause such damage to cells deep inside the body.
9. How can alpha, beta, and gamma radiation be distinguished using an electric or magnetic field?
Their different charge properties cause them to behave uniquely in an external field, which allows for easy identification. When a beam containing all three passes through a uniform electric or magnetic field:
- Alpha particles, being positively charged (+2), are deflected in one direction.
- Beta particles, being negatively charged (-1), are deflected in the opposite direction. Due to their much smaller mass, they are deflected more significantly than alpha particles for the same field strength.
- Gamma rays, having no charge, are completely unaffected and pass straight through without any deflection.
