Q 12-08-035JEE MainJEE Main 2026 (2 Apr, Shift 1)Easy
An electromagnetic wave travelling in **x-direction** is described by field equation
$E_y=300\sin\omega\left(t-\dfrac{x}{c}\right)$.
If the electron is restricted to move in **y-direction** only with speed of $1.5\times10^{6}$ m/s then ratio of maximum electric and magnetic forces acting on the electron is ______.
Answer: (A) $200$
The magnetic field of the wave is along $z$, perpendicular to the electron's velocity (along $y$), with $B_0=\dfrac{E_0}{c}$.
$$\frac{F_E}{F_B}=\frac{eE_0}{evB_0}=\frac{c}{v}=\frac{3\times10^{8}}{1.5\times10^{6}}=200$$
Solution by Sreeraj P, M.Sc Physics