Question

A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity, then :

• A. its velocity will decrease
• B. its velocity will increase
• C. it will turn towards right of direction of motion
• D. it will turn towards left of direction of motion

Answer 1

Answer: (A)

its velocity will decrease

Answer 2

When $\overrightarrow{E}$, $\overrightarrow{V}$ and $\overrightarrow{B}$ are all along same direction, then magnetic force experienced by electron is zero while electric force is acting opposite to velocity of electron, so velocity of electron will decrease.