What is intensity of electromagnetic wave? Give Its relation in terms of electric field E and magnetic field B

The intensity of an electromagnetic wave refers to the power carried by the wave per unit area. It is a measure of how much energy the wave transmits through a given surface area in a specific amount of time.

Defining Intensity

Intensity (I) can be mathematically expressed as:

• I = P/A

where P is the power and A is the area through which the power is passing.

Relation to Electric and Magnetic Fields

The intensity of an electromagnetic wave is also related to its electric field (E) and magnetic field (B). The relationship can be described by the formula:

• I = (1/2) * ε₀ * c * E²
• I = (1/2) * (B²/μ₀) * c

In these equations:

• ε₀ is the permittivity of free space.
• μ₀ is the permeability of free space.
• c is the speed of light in a vacuum.

Understanding the Relationship

From these formulas, we can see that the intensity of the wave is directly proportional to the square of the electric field and also to the square of the magnetic field. This means that as the strength of either the electric or magnetic field increases, the intensity of the wave also increases.