Short Answer

In an electromagnetic (EM) wave, the electric field and the magnetic field are closely linked. They oscillate at right angles to each other and also at right angles to the direction in which the wave travels. This perpendicular arrangement makes EM waves transverse in nature.

The changing electric field produces a changing magnetic field, and the changing magnetic field produces a changing electric field. Because of this continuous interaction, the wave can move forward even without a medium. This perfect connection between both fields is what allows EM waves to travel through space.

Detailed Explanation :

Relationship Between Electric and Magnetic Fields in an EM Wave

The relationship between electric and magnetic fields in an electromagnetic wave is one of the most important principles in physics. These two fields are not separate or independent; they are deeply connected. They work together to create and sustain the electromagnetic wave as it travels through space. This relationship was clearly explained by James Clerk Maxwell, whose equations describe how changing electric and magnetic fields generate each other.

The electric and magnetic fields in an EM wave oscillate in a coordinated manner. If one field increases or decreases, the other field also changes in the same rhythm. This synchronized behaviour allows the wave to propagate smoothly in the forward direction.

Mutual Generation of Fields

One of the core ideas of electromagnetism is that:

• A changing electric field produces a changing magnetic field.
• A changing magnetic field produces a changing electric field.

This means that the fields do not exist separately. When the electric field varies, it gives rise to a magnetic field, and when the magnetic field changes, it produces an electric field. This continuous process creates a self-supporting wave. As the wave moves, the fields keep regenerating each other without the need for particles or matter.

This is the main reason why electromagnetic waves can travel through vacuum.

Perpendicular Orientation of Fields

In an EM wave, the electric and magnetic fields are always arranged in a perpendicular manner:

• The electric field (E) vibrates in one direction.
• The magnetic field (B) vibrates in a direction perpendicular to the electric field.
• The wave moves in a direction that is perpendicular to both E and B.

Thus, all three directions—electric field, magnetic field, and wave propagation—are at right angles to each other. This makes the electromagnetic wave a transverse wave.

For example, if the electric field oscillates up and down, the magnetic field will oscillate sideways, and the wave will move forward.

Same Frequency and Phase

Another important part of their relationship is that the electric and magnetic fields oscillate with:

• The same frequency, meaning they vibrate the same number of times per second.
• The same phase, meaning they reach their maximum and minimum values at the same moment.

This matching behavior ensures the wave remains stable and balanced. If the fields did not have the same frequency and phase, the wave would not propagate correctly.

Energy Shared Between Fields

In an electromagnetic wave, energy is carried by both fields. Half of the total energy is stored in the electric field and the other half in the magnetic field. Together, they transport energy from one place to another. This energy can travel through vacuum or through different materials.

For example:

• Sunlight carries energy to Earth through electromagnetic waves.
• Radio waves carry sound information to our radios.
• Microwaves carry energy to heat food.

In all these cases, both fields work together to transport energy.

How the Fields Support Wave Travel

Because the electric and magnetic fields constantly create each other, the wave can travel continuously. Here’s how it works:

1. A changing electric field produces a magnetic field around it.
2. This magnetic field then changes and produces a new electric field.
3. The new electric field produces another magnetic field.
4. This chain continues endlessly as the wave travels forward.

This self-propagating mechanism is the reason why electromagnetic waves do not require any medium and can travel across empty space.

Examples in Daily Life

We observe the relationship between electric and magnetic fields around us every day, even if we can’t see the fields:

• Light from the Sun is an EM wave made of linked electric and magnetic fields.
• Radio signals sent to mobile phones travel through EM waves.
• Wi-Fi, Bluetooth, and TV signals all use these linked fields.
• X-rays and gamma rays use extremely fast oscillating fields.

Every type of electromagnetic wave—from long radio waves to short gamma rays—has the same relationship between electric and magnetic fields.

Proof Through Polarization

Polarization of light is a strong proof of the perpendicular relationship between fields. Polarization filters allow vibrations only in one direction. Since only transverse waves can be polarized, this confirms that electric and magnetic fields oscillate at right angles.

When light passes through a polarizing filter, one field direction gets blocked. The magnetic field automatically aligns because it is perpendicular to the electric field.

Maxwell’s Contribution

Maxwell’s equations are the foundation of our understanding. He mathematically proved:

• Electric and magnetic fields are linked.
• They travel together as waves.
• The speed of these waves in vacuum is the speed of light.

His theory unified electricity, magnetism, and light.

Conclusion

In an electromagnetic wave, the electric and magnetic fields are tightly connected. They oscillate at right angles to each other and regenerate each other as they move. Their synchronized behaviour, perpendicular arrangement, and equal frequency allow the wave to propagate through space. This relationship is the basis of all electromagnetic radiation, from radio waves to light and X-rays.