Q16. The electric field in an electromagnetic wave is given by $\overrightarrow { \mathrm { E } } = \hat { i } 40 \cos \omega ( \mathrm { t } - z / \mathrm { c } ) \mathrm { NC } ^ { - 1 }$. The magnetic field induction of this wave is (in SI unit) : (1) $\overrightarrow { \mathrm { B } } = \hat { k } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$ (2) $\vec { B } = \hat { j } 40 \cos \omega ( t - z / c )$ (3) $\overrightarrow { \mathrm { B } } = \hat { i } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$ (4) $\overrightarrow { \mathrm { B } } = \hat { j } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$
Q16. The electric field in an electromagnetic wave is given by $\overrightarrow { \mathrm { E } } = \hat { i } 40 \cos \omega ( \mathrm { t } - z / \mathrm { c } ) \mathrm { NC } ^ { - 1 }$. The magnetic field induction of this wave is (in SI unit) :\\
(1) $\overrightarrow { \mathrm { B } } = \hat { k } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$\\
(2) $\vec { B } = \hat { j } 40 \cos \omega ( t - z / c )$\\
(3) $\overrightarrow { \mathrm { B } } = \hat { i } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$\\
(4) $\overrightarrow { \mathrm { B } } = \hat { j } \frac { 40 } { \mathrm { C } } \cos \omega ( \mathrm { t } - z / \mathrm { c } )$