Practice Problems: Electric Potential Due to Point Charges
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For all the problems below assume that V = 0 at infinity.
1. (easy) Determine the electric potential at 0.001 m from a charge of 2pC.
2. (easy) Refer to the scenario in question #1.
a. If a second charge (-2pC) was the same distance from the point of interest as the first charge, find the total electric potential at that point.
b. If the second charge was closer to the point of interest would the total potential be positive of negative?
3. (easy) Is the magnitude of the electric potential caused by point charges an absolute or a relative value. Explain your answer.
4. (moderate) Two charges are located on corners of a rectangle with a height of 0.05 m and a width of 0.15 m. The first charge (q1= -5x10-6 C) is located at the upper left hand corner, while the second charge (q2 = +2.0 x10-6 C) is at the lower right hand corner. Determine the electric potential at the upper right hand corner of the rectangle.
5. (moderate) What is the potential difference for a point at the right hand corner (call it point A) of the rectangle in question #2 relative to the lower left hand corner (call it point B)?
6. (moderate) Two charged particles are placed on the x axis of a coordinate system. The first (q1 = 2x10-6 C) is at the origin. The second (q2 = -5x10-6 C) is at x = 1.0 m. Determine a point in between these two charges where the electric potential is zero.
7. (moderate) Two charged particles are held in place on the x-axis of a coordinate system. Charge q1 (5 C) is at the origin. Charge q2 (3 C) is at x = 1 m. A relatively small positive test charge (q = 0.01 C, m = 0.001 kg) is released from rest at x = 0.5 m. Will the test charge move to the right or the left? Additionally, use the concepts of electric potential and electric potential energy to determine the speed of the test particle after it moves 0.1 m.