Electromagnetic Radiation vs Electromagnetic Waves
Energy is one of the primary constituents of the universe. It is conserved throughout the physical universe, never created or never destroyed but transforming from one form to another. Human technology, primarily, is based on the knowledge of methods to manipulate these forms, to produce a desired outcome. In physics, energy is one of the core concepts of investigation, along with the matter. Electromagnetic radiation was first explained by physicist James Clarke Maxwell in 1860`s.
More about Electromagnetic Radiation
Electromagnetic radiation is one among many forms of energy in the universe. Electromagnetic radiation originates from the electric and magnetic fields corresponding to an accelerating electric charge. When investigated closely, electromagnetic waves display two types of contrasting characteristics in nature. Since it displays wave like behavior, it is referred to as an electromagnetic wave. It also displays particle like properties, therefore, considered as a collection (stream) of energy packets (quanta).
In general, electromagnetic waves are emitted from a source due to one of the two causes; i.e. either thermal or nonthermal radiation mechanisms. Thermal emission is caused by excitation of electric charges and is completely dependent on the temperature of the system. Physical phenomena like black-body radiation free- free emission (Bremsstrahlung emission) in ionized gases and spectral line emissions belong to this category. Nonthermal emission is not dependent on the temperature and synchrotron radiation, gyrosynchrotron emission, and quantum processes belong to this category
Electromagnetic radiation carries energy away from the source. Ascribing to its particle nature, it has both momentum and angular momentum. Energy and momentum may be transferred, when interacted with matter.
More about Electromagnetic Waves
Electromagnetic radiation can be considered as a transverse wave, where an electric field and a magnetic field oscillate perpendicularly to each other and to the direction of propagation. The energy of the wave is in the electric and the magnetic fields of the electromagnetic waves, therefore, require no medium for propagation. In a vacuum, electromagnetic waves travel at the speed of light, which is a constant (2.9979 x 108ms-1). The intensity/strength of the electric field and the magnetic field has a constant ratio, and they oscillate in phase (i.e. the peaks and the troughs are occurring at the same time during propagation)
Electromagnetic waves have a frequency and a wavelength and satisfies the equation v=fλ. Based on the frequency (or wavelength) electromagnetic waves can be arranged in ascending (or descending) order to create the electromagnetic spectrum. Based on the frequency, the electromagnetic waves are classified into different ranges. Gamma, X, ultraviolet (UV), visible, infrared (IR), microwave, and radio are the major divisions in the classification of the electromagnetic spectrum. Light is relatively a small portion of the electromagnetic spectrum.
What is the difference between Electromagnetic Radiation and Electromagnetic Waves?
Electromagnetic radiation is a form of energy, which is originated by accelerating charges, whereas electromagnetic wave is a model used to explain the behaviour of the emissions.
(Simply the wave model is applied to the emission to explain its behaviour, hence called an electromagnetic wave)