In an Electromagnetic Wave,1)how Are the Electric and Magnetic Field $\overrightarrow { \mathbf { c } }$

question 4

Multiple Choice

In an electromagnetic wave,1) how are the electric and magnetic field directions related and 2) how is the direction of travel determined from their directions? ( $\overrightarrow { \mathbf { c } }$ is the velocity of the light wave. )

• A) \(\overrightarrow { \mathbf { E } } \| \overrightarrow { \mathbf { B } } ; \frac { \overrightarrow { \mathbf { c } } } { c } = \frac { \overrightarrow { \mathbf { E } } \times \overrightarrow { \mathbf { B } } } { | \overrightarrow { \mathbf { E } } \times \overrightarrow { \mathbf { B } } | }\) .
• B) \(\overrightarrow { \mathbf { E } } \| \overrightarrow { \mathbf { B } } ; \frac { \overrightarrow { \mathbf { c } } } { c } = \frac { \overrightarrow { \mathbf { B } } \times \overrightarrow { \mathbf { E } } } { | \overrightarrow { \mathbf { B } } \times \overrightarrow { \mathbf { E } } | }\) .
• C) \(\overrightarrow { \mathbf { E } } \perp \overrightarrow { \mathbf { B } } ; \frac { \overrightarrow { \mathbf { c } } } { c } = \frac { \overrightarrow { \mathbf { E } } \times \overrightarrow { \mathbf { B } } } { | \overrightarrow { \mathbf { E } } \times \overrightarrow { \mathbf { B } } | }\) .
• D) \(\overrightarrow { \mathbf { E } } \perp \overrightarrow { \mathbf { B } } ; \frac { \overrightarrow { \mathbf { c } } } { c } = \frac { \overrightarrow { \mathbf { B } } \times \overrightarrow { \mathbf { E } } } { | \overrightarrow { \mathbf { B } } \times \overrightarrow { \mathbf { E } } | }\) .
• E) \(\overrightarrow { \mathbf { E } } = \overrightarrow { \mathbf { B } } / c ; \frac { \overrightarrow { \mathbf { c } } } { c } = \frac { \overrightarrow { \mathbf { B } } \overrightarrow { \times } \mathbf { E } } { | \overrightarrow { \mathbf { B } } \times \overrightarrow { \mathbf { E } } | }\) .

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