PHYSICS 7E Lecture Notes - Lecture 14: International System Of Units, Electric Field, Electromagnetic Radiation
PHYSICS 7E - Lecture 14 - Electromagnetic Waves
*Images from University Physics, Young & Freedman
Visible Light -- Specific Wavelengths and Colors
Doppler Effect for Light
●Light exhibits a Doppler effect
○Remember, the Doppler effect is an apparent change in frequency due to the
motion of an observer or the source
●Since there is no medium required for light waves, only the relative speed, v, between
the source and the observer can be identified
●The equation also depends on the laws of relativity
f′=f√c−v
c+v
●v is the relative speed between the source and the observer
●c is the speed of light
●f’ is the apparent frequency of the light seen by the observer
●f is the frequency emitted by the source
●For v/c << 1, (1 ) f′=f+c
v
Poynting Vector
●The Poynting Vector is defined as
ES ≡1
μo×B
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PHYSICS 7E Full Course Notes
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Document Summary
Physics 7e - lecture 14 - electromagnetic waves. Remember, the doppler effect is an apparent change in frequency due to the motion of an observer or the source. Since there is no medium required for light waves, only the relative speed, v, between the source and the observer can be identified. The equation also depends on the laws of relativity f = f c v c+v. V is the relative speed between the source and the observer. F" is the apparent frequency of the light seen by the observer. F is the frequency emitted by the source. For v/c << 1, f = f (1 v. Its direction is the direction of propagation. Its magnitude reaches a maximum at the same instant as the fields. The magnitude of the vector represents the rate at which energy flows through a unit surface area perpendicular to the direction of the wave propagation. This is the power per unit area.
