Question

The electric field of EM waves is $6volt/m$. The magnetic field associated with the wave if the wave is propagating in the +x direction and the electric field along the y-axis is:

• A. ${10}^{-8}T\hat{k}$
• B. $2\times {10}^{-8}T\hat{k}$
• C. $3·0\times {10}^{-8}T\hat{k}$
• D. $4·0\times {10}^{-8}T\hat{k}$

Answer 1

The correct option is B

$2\times {10}^{-8}T\hat{k}$

Step 1: Given data

The electric field of electromagnetic waves$\left(E\right)$= $6volt/m$

Speed of light $c=3\times {10}^{8}m/s$

Step 2: Formula used

The magnetic field can be computed using the following formula:

$Electricfield\left(E\right)=Magneticfield\left(B\right)\times speedoflight\left(c\right)$

Step 3: Compute the magnetic field

Substitute the known values in the following formula:

$\begin{array}{rcl}B& =& \frac{E}{c}\\ & =& \frac{6}{3.0\times {10}^8}\\ & =& 2.0\times {10}^{-8}T\left(alongz-axis\right)or2.0\times {10}^{-8}T\hat{k}\end{array}$

Hence, option B is the correct answer.