[Physics Class Notes] on Types of Radiation Pdf for Exam

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. 

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.

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.

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.

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.