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1. Consider a 3 micro-Coulomb charge a short distance away from a 1 micro-Coulom

ID: 1785991 • Letter: 1

Question

1. Consider a 3 micro-Coulomb charge a short distance away from a 1 micro-Coulomb charge as shown below. Both charges are held in place preventing them from moving. 20 cm q1 3 HC q2 a) For each region (to left of ql, in the middle, to the right of q2) state whether the electric field of ql and the electric field of q2 point in the same direction, or opposite directions. b) Calculate the location (other than infinity) where the net electric field 0. c) For this scenario, there is no location (other than infinity) where the net electric potential-0. Explain why. For the next questions, change q2 to be negative 1 micro-Coulomb. d) Repeat parts a) and b) for this scenario. e) Calculate the location where net electric potential - 0. f) Calculate the electric potential energy of this configuration of charges. g) Suppose ql and q2 start out infinitely far apart. How much work must you do on the charges to bring them to the configuration in this problem? (Hint: Think about how this question relates to the question in part f)

Explanation / Answer

let E1 be the field due to q1 and E2 be the field due to q2

a) to the left of q1

E1 and E2 are in same direction

in the middle

E1 and E2 are in opposite directions

to the right of q2

E1 and E2 are is same direction

b) E1 = E2 =


k*q1/x^2 = k*q2/(0.2-x)^2

3/x^2 = 1/(0.2-x)^2

at x = 0.126 to the right of q1 ,net electric field is zero


c) Electric field is vector quantity and electric potential is scalar quantity


so electric potential is not zero due to two positive charges

d)

to the left of q1

E1 and E2 are in opposite direction

in the middle

E1 and E2 are in same directions

to the right of q2

E1 and E2 are is opposite direction

b) E1 = E2 =


k*q1/x^2 = k*q2/(0.2-x)^2

3/x^2 = 1/(0.2+x)^2

at x = 0.126 to the left of q1 ,net electric field is zero