The magnetic field of an Electromagnetic Wave is given by

$B_y = 3 × 10^{-7} sin (10^3 x + 6.29 ×10^{12}t)$

The wavelength of the Electromagnetic Wave is

0.63 cm

Given, $B_y = 3 × 10^{-7} sin (10^3 x + 6.29 ×10^{12}t)$

Comparing with the general equation

$B_y = B_0 sin (kx + ωt)$

we get $ k = 10^3$

or $ \frac{2\pi}{λ} = 10^3 $

$⇒ λ = \frac{2\pi}{10^3}$

$ = 6.28 × 10^{-3}$ m

$ = 0.63 cm$