Question 145: EM waves

Question

A plane electromagnetic wave of frequency 50 MHz travels in free space along the  positive x-direction. At a particular point in space and time, $\overrightarrow E  = 6.3\widehat j\,V/m.$ The corresponding magnetic field $\overrightarrow {B,} $ at that point will be :

Accepted Answer

Given, $\overrightarrow E  = 6.3\widehat j$
$ 	herefore $   $\left| {\overrightarrow E } ight| = \sqrt {{{\left( {6.3} ight)}^2}}  = 6.3$
$ 	herefore $   $\left| {\overrightarrow B } ight| = {{\left| {\overrightarrow E } ight|} \over C}$
$ = {{6.3} \over {3 	imes {{10}^8}}}$
$ = 2.1 	imes {10^{ - 8}}\,$ T
Now we have to find the direction of $\overrightarrow B $.
We know, $\widehat E 	imes \widehat B = \widehat C$ and given $\overrightarrow E $ is in y-direction and wave moving in positive x-direction.
$ 	herefore $   $\widehat J 	imes \widehat B = \widehat i$
$ \Rightarrow $   $\widehat B = \widehat K$
$ 	herefore $   $\overrightarrow B  = \left| {\overrightarrow B } ight|\widehat B$
$ = 2.1 	imes {10^{ - 8}}\,\widehat K\,T$

Answer

18.9 $ 	imes $ 10
$-$8
$\widehat k$T

Answer

2.1 $ 	imes $ 10
$-$8
$\widehat k$T

Answer

6.3 $ 	imes $ 10
$-$8
$\widehat k$T

Answer

18.9 $ 	imes $ 10
8
$\widehat k$T

EM waves

A plane electromagnetic wave of frequency 50 MHz travels in free space along the positive x-direction. At a particular point in space and time, \overrightarrow E = 6.3\widehat j\,V/m. The corresponding magnetic field \overrightarrow {B,} at that point will be :

Choose the correct answer: