Maximum field strength

Definition

Maximum field strength is the peak value of the electric or magnetic field in an electromagnetic wave. It represents the highest intensity of the field at any point in time.

5 Must Know Facts For Your Next Test

1. The maximum field strength of an electromagnetic wave is directly related to its amplitude.
2. In free space, the maximum electric and magnetic fields are perpendicular to each other and to the direction of wave propagation.
3. The maximum value of the electric field ($E_{max}$) and magnetic field ($B_{max}$) are related by $E_{max} = c \cdot B_{max}$, where $c$ is the speed of light in a vacuum.
4. $E_{max}$ can be calculated using $E_{max} = \sqrt{2I / c\varepsilon_0}$, where $I$ is the intensity of the wave, $c$ is the speed of light, and $\varepsilon_0$ is the permittivity of free space.
5. The energy density in an electromagnetic wave is proportional to the square of its maximum field strength.

Review Questions

• How are the maximum electric and magnetic fields oriented relative to each other in an electromagnetic wave?
• What equation relates maximum electric field strength and magnetic field strength?
• How can you calculate $E_{max}$ using wave intensity?

Related terms

Amplitude: The amplitude of a wave is its maximum displacement from equilibrium position; for electromagnetic waves, it corresponds to maximum electric or magnetic field strength.

$c$ (Speed of Light): $c$ refers to the constant speed at which light travels in a vacuum, approximately equal to $3 \times 10^8$ meters per second.

$\varepsilon_0$ (Permittivity of Free Space): $\varepsilon_0$, also known as vacuum permittivity, is a physical constant that describes how an electric field affects and is affected by a vacuum. Its approximate value is $8.85 \times 10^{-12}$ farads per meter.