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) it will turn towards right of direction of motion
(b) it will turn towards left of direction of motion
(c) its velocity will decrease
(d) its velocity will increase

Answer 1

(c) : Magnetic field applied parallel to motion of
electron exerts no force on it as θ = 0 and force = Bevsinθ = zero

Electric field opposes motion of electron which carries a negative charge
Therefore, velocity of electron decreases.