For plane electromagnetic waves propagating in the z-direction , which one of the following combinations gives the correct possible direction for `vecE and vecB` field respectively ?

Options

A. `(hati+2hatj)` and `(2hati-hatj)`
B. `(-2hati-3hatj)` and `(3hati-2hatj)`
C. `(2hati+3hatj)` and `(hati+2hatj)`
D. `(3hati+4hatj)` and `(4hati-3hatj)`

Answer

B

Explanation

The direction of propogation of electromagnetic wave is along `vecExxvecB`
Also `vecE.vecB=0`
When `vecE` is along `-2hati-3hatj`
And `vecB` is along `3hati-2hatj`
Then
`vecExxvecB=(-2hati-3hatj)xx(3hati-2hatj)`
`=4hatk+9hatk`
`=13hatk` is along +ve direction also
`vecE.vecB=0`