Question

Electromagnetic wave is produced by oscillating electric and magnetic fields \(E^{-}\) and \(B^{-}\). Choose only the incorrect statement from the following (A) \(\mathrm{E}^{-}\) is perpendicular to \(\mathrm{B}^{-}\). (B) \(E^{-}\) is perpendicular to the direction of propagation of the wave (C) \(\mathrm{B}^{-}\) is perpendicular to the direction of propagation of the wave (D) \(E^{-}\) is parallel to \(\mathrm{B}^{-}\)

Short answer

The incorrect statement is (D) \(E^-\) is parallel to \(B^-\), as electric and magnetic fields in electromagnetic waves are always perpendicular to each other, not parallel.

Step-by-step solution

Statement A

\(E^- \) is perpendicular to \(B^-\). This statement is true as electric and magnetic fields in electromagnetic waves are always perpendicular to each other. They both oscillate at right angles to one another.

Statement B

\(E^-\) is perpendicular to the direction of propagation of the wave. This statement is also true. The electric field oscillates at a right angle to the direction of the wave's propagation.

Statement C

\(B^-\) is perpendicular to the direction of propagation of the wave. This statement is correct as well. The magnetic field also oscillates at a right angle to the direction of the wave's propagation.

Statement D

\(E^-\) is parallel to \(B^-\). This statement is false. As mentioned earlier, the electric and magnetic fields in electromagnetic waves are always perpendicular to each other, not parallel. Thus, the incorrect statement is (D) \(E^-\) is parallel to \(B^-\).

Key concepts

Oscillating Fields

Electromagnetic waves are fascinating entities that embody oscillating fields. These waves are created by the movement, or oscillation, of electric and magnetic fields. Picture a waving flag; similarly, these fields swing back and forth in a rhythmic motion. This oscillation is not a mere oscillation in isolation but rather orchestrated. The electric field and the magnetic field wiggle perpendicularly to each other, creating a harmonious dance. This dance is a fundamental property of electromagnetic waves and is responsible for how they propagate through space.

The dual oscillation in perpendicular directions is what differentiates electromagnetic waves from other types of waves, making them unique. The oscillation of these fields is vital in influencing how the wave travels and interacts with the environment it moves through. Understanding this concept helps in grasping how signals such as light and radio waves carry energy and information over distances.

Electric Field

An electric field is a region around a charged particle where other charged particles experience a force. In the context of electromagnetic waves, the electric field component is a vector quantity that oscillates back and forth. This oscillation occurs perpendicular to both the magnetic field and the direction the wave is traveling.

Imagine the electric field as lines that can exert a push or pull on charged particles passing through them. As part of an electromagnetic wave, these lines move up and down (oscillate), much like ripples on the surface of a pond when a stone is thrown in.

This up-and-down movement is what we refer to as the oscillating electric field. This property allows electromagnetic waves to transfer energy as they move through space. Understanding the nature of electric fields is crucial for exploring how they contribute to wave propagation and the overall behavior of electromagnetic waves.

Magnetic Field

A magnetic field is an area where magnetic forces are exerted, and it exists around magnets or moving charges. In electromagnetic waves, the magnetic field works in tandem with the electric field. This field also oscillates and it does so in a manner that is perpendicular to the electric field.

Just like the electric field, the oscillating magnetic field provides the mechanism for the wave to carry energy. Imagine lines that move and oscillate side to side; this is how the magnetic field behaves. These oscillations aid in the transportation of signals through various media or even in vacuum.

With its perpendicular orientation to both the electric field and the wave's direction, the magnetic field is pivotal in maintaining the wave structure. Comprehending its role helps demystify the way electromagnetic waves navigate their environment, affecting everything from communication systems to how we perceive light.

Wave Propagation

Wave propagation refers to the manner in which waves travel through a medium or through space. In electromagnetic waves, propagation is possible because of the intertwined oscillating electric and magnetic fields. These fields provide the dynamic push and pull that allow the wave to move.

As the electric and magnetic fields oscillate perpendicular to the direction of travel, the electromagnetic wave advances forward. Picture a snake slithering; similarly, the wave moves forward while its components oscillate, enabling the transport of energy and information.

Electromagnetic waves do not require a medium to travel through, unlike sound waves. This unique property enables them to propagate through the vacuum of space. Understanding wave propagation in this context is essential for explaining how electromagnetic signals, such as light, radio, and microwaves, can reach us from distant sources like the sun or distant galaxies. It encapsulates how electromagnetic waves are capable of transmitting energy over vast distances efficiently.