Exam 1 As a general rule, show your work. Extra scratch paper is available. Feel
ID: 1316228 • Letter: E
Question
Exam 1 As a general rule, show your work. Extra scratch paper is available. Feel free to write what you are thinking and what is perhaps tripping you up. Calculators are allowed, but cell phones and notes are not. You may not share calculators. Equations and constants are provided on the back. You may have the entire class period to complete the exam. When you are done, please turn in your exam and you are free to leave for the day 1. For the picture below, 91-3t1C, = 2 C, and Q,--3pC Qi 30 yem O 1 03 3cm 3MC (a) Calculate the electric potential V at point A. (10 points)Explanation / Answer
V(A) = (k*Q1) / (3cm) + (k*Q2) / (5cm) - (k*Q3) / (4cm)
V(A) = (k*3*10^(-6)) / (3*10^(-2)) + (k*2*10^(-6)) / (5*10^(-2)) - (k*3*10^(-6)) / (4*10^(-2))
V(A) = 585*10^3 V
(B):
E(A) = (k*Q1) / (3cm)^2 i = (k*3*10^(-6)) / (3*10^(-2)^2) = 30*10^(6) i V/m
E(B) = [(k*Q2) / (5cm)^2 ] * ((3/5)*i + (4/5)*j) = [ (k*2*10^(-6)) / (5*10^(-2)^2) ]* ((3/5)*i + (4/5)*j)
E(B) = 4.32 *10^(6) i + 5.76*10^(6) j V/m
E(C) = - (k*Q3) / (4cm)^2 j = - (k*3*10^(-6)) / (4*10^(-2)^2) j = -16.875 *10^(6) j V/m
E(net) = E(A) + E(B) + E(C)
E(net) = 34.32 * 10^(6) i - 11.115 * 10^(6) j V/m