Question

uniform electric field of magnitude 365 N/C pointing in the positive x-direction acts on an electron, which is initially at rest. The electron has moved 3.00 cm. (a) What is the work done by the field on the electron? 1.753e-18 J (b) What is the change in potential energy associated with the electron? J

Answer 1

a) W = - 1.752 10⁻¹⁸ J, b) U = + 1.752 10⁻¹⁸ J

Step-by-step explanation:

a) work is defined by

W = F . x

the bold letters indicate vectors, in this case the force is electric

F = q E

we substitute

F = q E x

the charge of the electron is

q = - e

F = - e E x

let's calculate

W = - 1.6 10⁻¹⁹ 365 3 10⁻²

W = - 1.752 10⁻¹⁸ J

b) the change in potential energy is

U = q ΔV

the potential difference is

ΔV = - E. Δs

we substitute

U = - q E Δs

the charge of the electron is

q = - e

U = e E Δs

we calculate

U = 1.6 10⁻¹⁹ 365 3 10⁻²

U = + 1.752 10⁻¹⁸ J