Question

A moving electron enters an electric field. The initial velocity of the electron is in the same direction as the electric field. How will the electric field affect the motion of the electron?
A. The electron will accelerate in the opposite direction of its motion.
B. The electron will accelerate in the same direction as its motion.
C. The electron’s speed will remain constant as it changes direction.
D. The electron’s speed will increase as it changes direction.

Answer 1

The electric field will exert a force that accelerates the charged particle. The electric field has a direction, positive to negative. ... If a positive charge is moving in the same direction as the electric field vector the particle's velocity will increase. If it is moving in the opposite direction it will decelerate.THINK ABOUT IT!!!!!! the answer is here

Answer 2

Answer: Option A "The electron will accelerate in the opposite direction of its motion."

Explanation:

The force between an electric field and a charge is written as:

F = q.E

Where the E is a vectorial field, so it has a given direction.

Now, the electron moves in the same direction that the field is pointing, so the dot product can be written as a scalar product, and we have:

F = q*E

Now, we also know that the charge of an electron is negative and is -e. so the force will be:

F = -e*E

From the minus sign, we can see that the force is opposite to the direction of the field, this would mean that the electron is accelerated in the opposite direction of its motion (because the initial motion was in the same direction that the field)

So the correct option is A