Question

The magnetic field of an electromagnetic wave is given by
$B_y=3\times 10^{-7}sin\left(10^{3}x+6.28\times 10^{12}t\right)$ .
The wavelength of the electromagnetic wave is

• A. $6.28cm$
• B. $3.14cm$
• C. $0.63cm$
• D. $0.32cm$

Answer 1

Answer: (C)

Given, $B_y=3\times 10^{-7}sin(10^{3}x+6.28\times 10^{12}t)$
Comparing with the general equation
$B_y=B_{0}sin(kx+\omega t)$
we get $k=10^3$
or $\frac{2\pi }{\lambda }=10^3\left[k=\frac{2\pi }{\lambda }\right]$
$\Rightarrow \lambda =\frac{2\pi }{10^3}$
$=6.28\times 10^{-3}m$
$=0.63cm$