The magnetic field in a plane electromagnetic wave is given by $\mathrm{B}_{\mathrm{y}}=2 \times 10^{-7} \sin \left(0.5 \times 10^3 \mathrm{x}+1.5 \times 10^{11} \mathrm{t}\right) \mathrm{T}$. The electromagnetic wave is:
Answer & explanation
Correct answer: option 3
$\mathrm{B}_{\mathrm{y}}=2 \times 10^{-7} \sin \left(0.5 \times 10^3 \mathrm{x}+1.5 \times 10^{11} \mathrm{t}\right) \mathrm{T}$
Comparing with the standard equation, we get
$\mathrm{B}_{\mathrm{y}}=\mathrm{B}_0 \sin (\mathrm{kx}+\omega \mathrm{t})$
k = $0.5 \times 10^3$
$\Rightarrow \lambda=\frac{2 \pi}{0.5 \times 10^3}$ = 0.01256 m
The wavelength range of microwaves is 10-3 m to 0.3 m. The wavelength of this wave lies between 10-3 m to 0.3 m, so the equation represents a microwaves.