Moving Charges And Magnetism Ques 11

11. In a certain region of space electric field $\vec{E}$ and magnetic field $\vec{B}$ are perpendicular to each other and an electron enters in region perpendicular to the direction of $\vec{B}$ and $\vec{E}$ both and moves undeflected, then velocity of electron is

[2001]

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Answer:

Correct Answer: 11.(a)

Solution:

  1. (a) Electron moves undeflected if force exerted due to electric field is equal to force due to magnetic field.

$q|\vec{v} || \vec{B}|=q|\vec{E}| \Rightarrow|\vec{v}|=\frac{|\vec{E}|}{|\vec{B}|}$