Physics - Magnetism Question with Solution | TestHub

Here, $\vec{E}$ and $\vec{B}$ are acting along $x$-axis and $\vec{v}$ is along $y$-axis i.e. perpendicular to both $\vec{E}$ and $\vec{B}$. Therefore, the path of charged particle is a helix with increasing speed. Speed of particle at time $t$ is $v=\sqrt{v_x^2+v_y^2}$
Here, $v_y=v_0;v_x=\frac{q{E}_0}{m}t$ and $v=\frac{\sqrt{5}}{2}{v}_0$ Putting values in $(\mathrm{i})$, we get $t=\frac{m{v}_0}{2q{E}_0}$