Problem 11-55 Potential and kinematics in thundercloud

Under a particular thundercloud, there is a uniform electric field of 9.3×103V/m upward.

An electron in the field, initially at rest, travels freely for 3.5×106m before undergoing a collision with a gas molecule. Just before it hits the molecule, what is its speed? Use energy methods.

[Ans. 1.1×105m/s]


Let's start with a diagram showing the field direction and the direction of motion of the electron. Which is correct?

(A)

Diagram A showing the field direction and the direction of motion of the electron

 

(B)

Diagram B showing the field direction and the direction of motion of the electron

 

(C)

Diagram C showing the field direction and the direction of motion of the electron