Question

The magnetic field in a plane electromagnetic wave is given by $=2\times {10}^{-7}\sin (0.5\times {10}^{3}x+1.5\times {10}^{11}t)$. This electromagnetic wave is

• A. Visible light
• B. Infrared
• C. Microwave
• D. Radiowave

Answer 1

The correct option is C Microwave

The magnetic field in a plane of electromagnetic wave is given by

$B=2\times {10}^{-7}sin(0.5\times {10}^{3}x+1.5\times {10}^{11}t)$

from the above, $K=0.5\times {10}^3=$ propagation constant

$K=\frac{2\pi }{\lambda }$ where, $\lambda =$ wavelength of wave

$\lambda =\frac{2\times 3.14}{0.3\times {10}^3}$

$\lambda =1.256\times {10}^{-2}m$

$\lambda =1.256cm$

The electromagnetic wave is Microwave radiation in spectrum.