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

$B_{y}=5 \times 10^{-6} \sin 1000 \pi\left(5 x-4 \times 10^{8} t\right) T$. The amplitude of electric field will be :

In an electromagnetic wave, the magnitude of the electric field (E) and the magnetic field (B) are related by the speed of the wave (v), which can be represented as : <br/><br/>$E = Bv$ <br/><br/>Here, B is the magnetic field, E is the electric field, and v is the speed of the electromagnetic wave. <br/><br/>In the given problem, the peak value of the magnetic field is given as : <br/><br/>$B_0 = 5 \times 10^{-6} T$ <br/><br/>The wave speed (v) can be calculated from the given equation for the magnetic field, using the relationship between frequency (f), wave number (k), and speed : <br/><br/>$$v = \frac{\omega}{k} = \frac{1000 \pi \times 4 \times 10^8}{1000 \pi \times 5} = 8 \times 10^7 m/s$$ <br/><br/>Substituting these values into the equation for the electric field gives the peak value of the electric field : <br/><br/>$E_0 = B_0 v = 5 \times 10^{-6} T \times 8 \times 10^7 m/s = 4 \times 10^2 V/m$