Name: Nature of Electromagnetic Waves
Uploaded: 2019-07-19
Duration: 5 min 57 s
Description: Have you ever wondered why light doesn’t push you, the way wind or water do? Or does it? Watch this video to learn how light exerts a force on us.

Question

Give the brief history of discovery of knowledge of electromagnetic waves.

Accepted Answer

Faraday experimentally concluded that a magnetic field changing with time produces an electric field in that region and thus formulated the laws of electromagnetic induction.

Maxwell in $1865$ , based on "principle of symmetry in nature" postulated that the reverse should also true.i.e an electric field changing with time should produce a magnetic field in that region.This means that either field changing with time should produce the other field in that region. On this base Maxwell concluded that the variation in mutually perpendicular electric and magnetic fields will produce disturbances in space and called them electromagnetic waves These have properties of transverse waves and can travel in vacuum.

Maxwell also found the speed of electromagnetic wave in vacuum given by the relation

$c = \frac{1}{\sqrt{μ_{0} ε_{0}}}$ where $μ_{0}, ε_{0}$ are the permeability and permittivity of free space, whose value comes out to be $3 \times 10^{8} m / s$ , which is also the speed of light.This showed that the light is an electromagnetic wave.

In 1888, Hertz demonstrated experimentally the production of electromagnetic waves of wavelength $6 m$ using a spark oscillator and detecting them successfully beyond several meters. In $1895$ J.C Bose was able to produce e.m waves of $5 mm - 25 mm$ wavelength, but his experiment was confined to laboratory only.

In $1896$ Marconi by modification in Hertz's arrangement able to generate electromagnetic waves was able to establish wireless communication across English Channel.

This was the beginning of modern communication era.

Embibe Experts Solutions for Chapter: Electromagnetic Waves, Exercise 1: Exercise

Embibe Experts Physics Solutions for Exercise - Embibe Experts Solutions for Chapter: Electromagnetic Waves, Exercise 1: Exercise

Questions from Embibe Experts Solutions for Chapter: Electromagnetic Waves, Exercise 1: Exercise with Hints & Solutions

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