To apply Problem-Solving Strategy 18.1 Calculation of potential.
"Remember that potential is simply potential energy per unit charge. Understanding this simple statement can help you to obtain a solution.
To find the potential V?at a point due to any collection of point charges q?1??, q?2??, q?3??,... at distances r?1??, r?2??, r?3??,..., from q?′??, use V=U?q?′???=k(q?1??r?1???+q?2??r?2???+q?3??r?3???+...)?.
If you are given or can find the electric field, it may be easier to calculate the work done on a test charge during a displacement from point a to point b. When it's appropriate, make use of your freedom to define V?to be zero at some convenient place. For point charges, this will usually be at infinity, but for other distributions of charge, it may be convenient or necessary to define V?to be zero at some finite distance from the charge distribution-say, at point b. This is just like defining U?to be zero at ground level in gravitational problems."
QUESTIONS
Three point charges with values q1 = 8.00 nC , q2 = 3.00 nC , and q3 = 7.00 nC are placed on three consecutive corners of a square whose side measures s = 2.00 m . Point A lies at the fourth corner of the square, diagonally across from q2. Point B lies at the center of the square. What are the values of the electric potential at point A and at point B? How much energy (supplied as work) is required to move a test charge q4 = 2.00 nC from point A to point B? Assume the zero of electric potential is chosen to be at infinity.
1.) What is the electric potential at point A? Express your answer numerically in volts.
2.) What is the electric potential at point B? Express your answer numerically in volts.
3.) How much energy (supplied as work) is required to move a test charge q4 = 2.00 nC from point A to point B?
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