Question

A uniform electric field and a uniform magnetic field are produced pointing in the same direction. An electron is projected with its velocity pointed in the same direction.Then:

• A. the electron will turn to its right
• B. the electron will turn to its left
• C. the electron velocity will increase in magnitude
• D. the electron velocity will decrease in magnitude

Answer 1

Answer: (D)

the electron velocity will decrease in magnitude

$\overrightarrow{v}\parallel \overrightarrow{B}$
therefore, $\overline{B}$ will not have any effect on it, but $\overline{E}$ will apply force in opposite direction thus, deaccelerating it.