Chapter 25: Electromagnetic Waves Reference Tools & Resources

Reference Tools & Resources

I. Key Terms and Phrases

electromagnetic wave: a wave consisting of oscillating electric and magnetic fields that propagates at the speed of light.

speed of light: the constant speed at which light travels in vacuum.

electromagnetic spectrum: the full (infinite) range of frequencies (and wavelengths) of electromagnetic waves.

radiation pressure: the pressure exerted by electromagnetic waves.

polarized light: when the electric field of an electromagnetic wave oscillates along a specific direction.

polarizer: an object that absorbs the component of the electric field of an electromagnetic wave that is perpendicular to its transmission axis.

transmission axis: the direction in a polarizer that transmits a polarized electromagnetic wave without loss of intensity if it is polarized along this direction.

law of Malus: the expression for the intensity that results when polarized light passes through a polarizer.

analyzer: a second polarizer used to analyze the polarized light that emerges from a polarizer.

II. Important Equations

Name/Topic	Equation	Explanation
Doppler effect		The Doppler effect for light, assuming u <<c.
electromagnetic spectrum	c = lf	The relationship between the wavelength and frequency of electromagnetic waves.
energy density		The average energy density of electromagnetic waves.
electromagnetic waves	E = cB	The relationship between E and B in an electromagnetic wave.
intensity		The instantaneous intensity of electromagnetic waves.
polarization	I = I0cos2q	The law of Malus for the intensity of light emerging from a polarizer.

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