JEE Previous Year Question

An electron with kinetic energy $5\text{eV}$ enters a region of uniform magnetic field of $3\text{μT}$ perpendicular to its direction. An electric field $E$ is applied perpendicular to the direction of velocity and magnetic field. The value of $E$, so that electron moves along the same path, is_____ ${\text{NC}}^{-1}$. ( Given, mass of electron $=9\times {10}^{-31}\text{kg}$, electric charge $=1.6\times {10}^{-19}C$ )

Topic: JEE PYQ

Answer: 4. Full step-by-step solution below.