Class 12th Physics Electromagnetic Waves NCERT Notes CBSE 2023

# Chapter 8 Electromagnetic Waves

Electromagnetic waves are an important chapter of Grade 12 Physics. Understanding the concepts explained in the chapter can help students achieve good results in the material. Therefore, it is very necessary to practice the questions in the Grade 12 Physics NCERT notes Chapter 8 Electromagnetic Waves. In this article, we have provided download links for chapter 8, microwave, visible, infrared, x-ray, and gamma-ray solutions. Vidyakul provides a set of more than 400 practice questions for sub-topics related to Chapter 8. Students should concentrate on solving all questions in the material provided by Vidyakul in order to score well.

### Points to Remember

Students can find the important points to remember from Class 12 Physics Chapter 8 below. Noting down the important points helps students to have a quick revision during the final exam preparation.

• Maxwell found an inconsistency in Ampere’s law and suggested the existence of an additional current, called displacement current.

• An accelerating charge produces electromagnetic waves. An electric charge oscillating harmonically with frequency Vv produces electromagnetic waves of the same frequency v.

• Electromagnetic waves with a wavelength of the order of a few meters were first produced and detected in the laboratory by Hertz in 18871887. He thus verified a basic prediction of Maxwell’s equations.

• Electric and magnetic fields oscillate sinusoidally in space and time in an electromagnetic wave. The oscillating electric and magnetic fields, EE and BB are perpendicular to each other, and to the direction of propagation of the electromagnetic wave.

• The spectrum of electromagnetic waves stretches, in principle, over an infinite range of wavelengths. Different regions are known by different names.

• Infrared waves are also known as heat waves.

### Topics and Sub-topics

At first, navigating the NCERT notes of electromagnetic waves may seem difficult for students. However, daily practice and understanding of the concepts will make the learning process easier. Students should solve as many questions as possible to master the topic and get maximum test scores.

All problems and solutions provided by Vidyakul are based on the latest program. Students can practice all the solutions for free and get high scores on the exam.

 S. No Topic Name Description 1 Displacement Current 2 Maxwell’s Equations 3 Sources of Electromagnetic Waves 4 Nature of Electromagnetic Waves 5 Electromagnetic Spectrum

### Few Important Questions

• What are the uses of ‘Infrared rays’?

Infrared rays are widely used for cosmetic applications such as treating skin injuries, smoothing wrinkles, reducing the occurrence of dandruff, blackheads, etc.

• What are the uses of ‘Electromagnetic’ waves?

Electromagnetic waves have a vast range of practical everyday applications that includes such diverse uses as communication by cell phone and radio broadcasting, WiFi, cooking, vision, medical imaging, and treating cancer.

• What is a ‘Displacement current’?

The displacement current was named as current because it is similar to the conduction current. displacement current is the current due to the changing of the electric field inside the plate of the capacitor.

### Practice Questions

1. By using the formula E = hν, obtain the photon energy in units of eV for different parts of the electromagnetic spectrum (for the energy of a quantum of radiation: photon).

2. What can you say about the directions of the electric and magnetic field vectors of a plane electromagnetic wave t which is traveling in vacuum along z-direction and the frequency of the wave is 50 MHz and find out what is its wavelength?

3. A radio can tune in to any station in the 8.3 MHz to 15 MHz bands. What is the corresponding wavelength band?