Class 12 Physics Electromagnetic Waves Formulas

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Senior Executive

Updated on Nov 4, 2025 17:29 IST

The Electromagnetic Waves chapter is one of the most significant chapters of Class 12 Physics for CBSE and competitive exam aspirants. Learn concepts and Practice numericals with the Electromagnetic Waves Class 12 formulas provided by Shiksha.

Often, when you solve the NCERT Exercise of class 12 physics chapters, you need a quick revision of formulas and concepts. Along with formulas, NCERT Notes for EM Waves are really useful for class 12 Boards to develop answer-writing skills in Chapter 8 of Physics Class 12.

This Class 12 Physics EM Waves Formula Sheet in the form of a table below will make your work easy. You can combine these formulas with the chapter-wise NCERT Solutions provided by Shiksha to get all your doubts cleared and get a crystal clear understanding.

Revise all the formulas through the table below:

Topic	Subtopic	Formula
Ampere-Maxwell Law	Line Integral of the Magnetic Field around a Closed Loop	$\oint B \cdot d l$
	Line Integral due to Conduction Current	$μ_{0} i_{c}$
	Line Integral due to Displacement Current	$\mu_0 \varepsilon_0 \dfrac{d\Phi_E}{dt}$
	Mathematical Formula	$\oint B \cdot d l = μ_{0} i_{c} + μ_{0} ε_{0} \frac{d Φ_{E}}{d t}$
Components of EM Wave	Electric Field	$E (x, t) = E_{0} \sin (k x - ω t) \hat{j}$
	Magnetic Field	$B (x, t) = B_{0} \sin (k x - ω t) k$
	Direction of propagation	Perpendicular to both E and B (Plane)
	Speed of the Wave (in vacuum)	$c = \frac{1}{\sqrt{μ_{0} ε_{0}}} \approx 3 \times 10^{8} m/s$
	Speed in terms of E and B	$\frac{E_{0}}{B_{0}} = c$
Electromagnetic Spectrum	Radio Waves	WaveLength: > 1 m Frequency: < 300 MHz
	Microwaves	WaveLength: 1 m – 1 mm Frequency: 300 MHz – 300 GHz
	Infrared (IR)	WaveLength: 1 mm – 700 nm Frequency: 300 GHz – 430 THz
	Visible Light	WaveLength: 700 nm – 400 nm Frequency: 430 THz – 750 THz
	Ultraviolet (UV)	WaveLength: 400 nm – 10 nm Frequency: 750 THz – 30 PHz
	X-Rays	WaveLength: 10 nm – 0.01 nm Frequency: 30 PHz – 30 EHz
	Gamma Rays	WaveLength: < 0.01 nm Frequency: > 30 EHz
Related Terms to EM Waves	Energy density	$u = \frac{1}{2} ε_{0} E^{2} + \frac{1}{2} \frac{B^{2}}{μ_{0}}$
Related Terms to EM Waves	Poynting Vector	$S = \frac{1}{μ_{0}} (E \times B)$

Complete Study Material for Class 12 Physics Chapter 8

Formulas are not the only thing needed to ace the board exam. Obviously, you need quick notes, solutions, exemplar solutions, important questions, and more. The table below has all you need. Go through it and utilize it as you like.

Electromagnetic Waves Class 12 Notes

EM Waves NCERT Exemplar Solutions

Class 12 Physics Chapter 8 NCERT Solutions

Class 12 Physics EM Waves - Quick Revision Notes

About the Author

nitesh singh

Senior Executive

Nitesh Singh, a science graduate and content creator, specializes in developing engaging Physics, Chemistry, and Mathematics resources for the K-12 segment. He crafts precise and pedagogically sound Q&As, comprehens Read Full Bio