Question

The figure shows the equipotential lines created by a distribution of source charges (not pictured here) along with five locations in space (a-e). (a) At each of the points indicated, draw the electric field vector (magnitude and direction). (b) An ion is placed, initially at rest at point c and allowed to move solely due to the electric force. At a later time, the ion is at point b. Is the ion positively or negatively charged? What is that ion’s speed at point b? Explain your reasoning. (c) At what location on the figure is the ion traveling the fastest? Explain. (d) If instead, you doubled the charge on the ion: how does the ion’s speed at point b change from your previous answer? how does the fastest speed of the ion change from the previous case? (be as numerical as possible, e.g., “double”) (e) A different charged object gains 5 µJ of kinetic energy as it moves from point b to a. What is its charge (include sign)? (f) When an electron is located at point d, it has velocity vo to the right. The electron reaches point e before it turns around. At a later time, the electron’s velocity is 2vo to the left. At what location on the figure is the electron located when this happens? Is there more than one answer?

300 V 200 V 300 V 100 V 200 V I titi Illelld а! ы le 1 250 V 250 V 350 V 150 V 50 V 150 V

Answer 1

solution (a) JE 300V 300V ev 2001 PV Tu UT- att 2500 3500 agov sov iso electric field vectors with magnitude and direction are shown. (6) As the ion moves from lower Potential as 200 v to higher Potential of 350 initially from rest so the ion is negatively Charged The ion first accelerate from Point C (200v) to the line at 3ro6 then it deaccelerate and reached to Paintb so speed of ion at b r o] (c) Ion is fastest at 350 V line. O speed will still be no and fastest speed at 350 V line but it becomes a time than Previous © 2x SO = 5x10-65 = (f) q = t looxióta At iso v lime in the right and also at 150V line in the left. (two answers)