An electron enters a crossed electrical and magnetic field region with a speed of $100 m s^{-1}$ along +x-axis and passes undeviated. The strength of magnetic field is 5.0 T and it acts along +z-axis. Give the electrical field in vector notations indicating its magnitude as well as direction:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → $\left(500 Vm^{-1}\right) \hat{j}$
for electron to remain undeviated,
$F_e=F_B$
$qE=q(V×B)$ [$q(V×B)$: Lorentz force]
$E=V×B$
$=(100\hat i)×(0.5)\hat k$
$=500\hat jV/m$