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Physics · Class 12

Transverse electromagnetic wave

Electromagnetic Waves

E and B oscillate in perpendicular directions, both transverse to propagation. Their peaks occur together in a vacuum plane wave. Change time to shift the field pattern.

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Transverse electromagnetic wave

மின்புலமும் காந்தப்புலமும் ஒன்றுக்கொன்று செங்குத்து; இரண்டும் அலை செல்லும் திசைக்கு செங்குத்து.

Key notes, relationships and model limits

Key relationship

E=E₀sin(kx−ωt); B=E/c; λ=c/f; ⟨S⟩=½ε₀cE₀².

Remember

E and B oscillate in perpendicular directions, both transverse to propagation. Their peaks occur together in a vacuum plane wave. Change time to shift the field pattern.

Common trap

Electric and magnetic fields are perpendicular to each other and to propagation in this vacuum plane wave; they oscillate in phase.

Model limits

Ideal monochromatic vacuum plane wave; x is propagation coordinate and graph ordinate is one transverse electric component. Time uses ns, frequency uses MHz.

What you will learn

Use the controls and plotted relation to explain transverse electromagnetic wave.

Try the experiment

Try both scenarios, change one control, and predict the result before checking the graph and readouts.

Think of it this way

Change one input while keeping the others fixed, as you would in a controlled experiment.

Worked example

At f=100 MHz, λ≈2.998 m. For E₀=10 V/m, B₀≈33.36 nT.

Why this matters

The model connects transverse electromagnetic wave with an observable reading. Check the equation and assumptions before applying it.

Before you start

SI units · algebra · graph reading

Check your understanding

For an electromagnetic plane wave in vacuum, E₀/B₀ equals?

Read the explanation

The speed of light c.

Course connection: Class XII Chapter 8. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.