Defination of Wave
Wave is the way of transport of energy without the transport of matter. In other words, a wave can be described as a disturbance that travels through a medium, transporting energy from its source to another location without transporting matter.
Types of Waves
Mainly there are two types of waves to transport energy from a location to another location.
1) Mechanical Waves
Mechanical waves are caused by a disturbance in the matter, whether solid, gas, liquid, or plasma. The matter that waves are traveling through is called a medium. Waves in water and sound waves in the air are two examples of mechanical waves.
2) Electromagnetic Waves
In the 1870’s, a Scottish scientist named James Clerk Maxwell told that when an electric field comes in contact with a magnetic field Electromagnetic waves are formed. The electric field and magnetic field of an electromagnetic wave are perpendicular to each other. Thus two fields become sources of each other and the wave propagates in a direction perpendicular to both the fields. These waves travel with a constant velocity of 3.00 x 108 ms-1 in a vacuum. Electromagnetic waves do not require a medium to propagate. This means that electromagnetic waves can travel in the vacuum of space also.
Electromagnetic radiation
Electromagnetic radiation is caused to electromagnetic waves, propagating through space, carrying electromagnetic radiant energy. Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays are examples of Electromagnetic radiation. All of these waves form part of the electromagnetic spectrum. Electromagnetic waves are created due to periodic changes of the electric or magnetic fields. The position of a specific electromagnetic wave within the electromagnetic spectrum can be known by either its frequency of oscillation or its wavelength. The entire electromagnetic spectrum, from the lowest to the highest frequency includes all radio waves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. All frequencies and wavelengths of electromagnetic radiation can be used for spectroscopy.
Frequency and Wavelength range of Electromagnetic Waves
| Type of Radiation | Frequency Range (Hz) | Wavelength Range |
| Gamma-rays | 1020 – 1024 | < 10-12 m |
| X-rays | 1017 – 1020 | 1 nm – 1 pm |
| Ultraviolet | 1015 – 1017 | 400 nm – 1 nm |
| Visible | 4 – 7.5*1014 | 750 nm – 400 nm |
| Near-infrared | 1*1014 – 4*1014 | 2.5 μm – 750 nm |
| Infrared | 1013 – 1014 | 25 μm – 2.5 μm |
| Microwaves | 3*1011 – 1013 | 1 mm – 25 μm |
| Radio waves | < 3*1011 | > 1 mm |
Electromagnetic waves are emitted by electrically charged particles undergoing acceleration and these waves can subsequently interact with other charged particles, exerting force on them.
Dual Personality of Electromagnetic Waves:
Scientists have observed that electromagnetic radiation has a dual “personality.” Besides acting like waves, it acts like a stream of particles (called “photons”) that have no mass. The photons with the highest energy correspond to the shortest wavelengths.
Uses of Electromagnetic Waves
Ultraviolet: Energy-efficient lamps, sun tanning, sterilization, vitamin D production Ozone depletion, etc.
Radio waves: Radio and television, accelerating charges, Remote controls, etc.
Microwaves: Satellite communications and thermal agitation, Ovens, Radar, Cell phone, etc.
Infrared: Electrical heaters, cooking food, electronic transitions, and infrared cameras, etc.
X-rays: Medical imaging and treatments, Inner electronic transitions and fast collisions security, etc.
Gamma rays: Medical imaging and treatments, nuclear medicine, security, etc.
Visible light: Fiber optic communications, thermal agitation and electronic transitions photosynthesis, human vision, etc.
In general, the applications of EM waves significantly depend on their corresponding frequency. Harnessing the capabilities of EM waves has led to great impacts on various fields such as wireless communication, industrial sensing/imaging, biomedical imaging and treatment, remote sensing, radar, security screening, etc.
Important Questions
Question 1: How are electromagnetic waves generated?
Answer: When an electric field comes in contact with a magnetic field Electromagnetic waves are formed. Electromagnetic waves are created due to periodic changes of the electric or magnetic fields.
Question 2: How are electromagnetic waves propagated?
Answer: Electromagnetic waves do not require a medium to propagate. This means that electromagnetic waves can travel in the vacuum of space also.
Question 3: What is the velocity of electromagnetic waves?
Answer: Electromagnetic waves travel with a constant velocity of 3.00 x 108 ms-1 in a vacuum.
Question 4: How is known the position of a specific electromagnetic wave?
Answer: The position of a specific electromagnetic wave within the electromagnetic spectrum can be known by either its frequency of oscillation or its wavelength.
Question 5: What is the way of transport of energy without the transport of matter?
Answer: Wave is the way of transport of energy without the transport of matter. In other words, a wave can be described as a disturbance that travels through a medium, transporting energy from its source to another location without transporting matter.
Question 6: What are the main types of waves to transport energy from a location to another location?
Answer: Mainly there are two types of waves to transport energy from a location to another location.
(a) Mechanical waves
(b) Electromagnetic waves
Question 7: What are mechanical waves?
Answer: Mechanical waves are caused by a disturbance in the matter, whether solid, gas, liquid, or plasma. The matter that waves are traveling through is called a medium. Waves in water and sound waves in the air are two examples of mechanical waves.
Question 8: What if electromagnetic radiation?
Answer: Electromagnetic radiation is caused to electromagnetic waves, propagating through space, carrying electromagnetic radiant energy. Electromagnetic waves are created due to periodic changes of the electric or magnetic fields. Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays are examples of Electromagnetic radiation.
Question 9: What is the dual personality of electromagnetic waves?
Answer: Scientists have observed that electromagnetic radiation has a dual “personality.” Besides acting like waves, it acts like a stream of particles (called “photons”) that have no mass. The photons with the highest energy correspond to the shortest wavelengths.
Question 10: What are the major applications of electromagnetic waves (EM)?
Answer: EM waves have led to great impacts on various fields such as wireless communication, industrial sensing/imaging, biomedical imaging and treatment, remote sensing, radar, security screening, etc.
