Question

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

• 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

Answer 2

Since electron is moving is parallel to the magnetic field, hence magnetic force on it $F _ { m } = 0$.

The only force acting on the electron is electric force which reduces it’s speed.