Answer:
The speed of electron is [tex]v = \frac{E}{B}[/tex]
Option (b) is correct.
Explanation:
Given:
A beam of electrons is sent in the positive x-direction in a region with a uniform magnetic field B in the positive y-direction and a uniform electric field E in the positive z-direction.
Electric force is given by :
⇒ [tex]F = qE[/tex]
Magnetic force is given by :
⇒ [tex]F = q (v \times B)[/tex]
[tex]F = qvB[/tex]
Compare both the forces,
[tex]qvB = qE[/tex]
[tex]v = \frac{E}{B}[/tex]
Therefore, the speed of electron is [tex]v = \frac{E}{B}[/tex]
