Question

Three charges are placed on the y-axis. The first, with charge 11nC, sits at y=5cm. The second, with charge -13nC, is at y=0cm. The third, -9nC, is at y=−5cm.

Part A

What is the electric potential on the x-axis at x=10cm?

Part B

What is the magnitude of the electric field at x=10cm?

Part C

What is the electric potential at x=−10cm?

Part D

What is the magnitude of the electric field at x=−10cm?

Answer 1

ga 11.18 cm 11.18 cm cm o TO+ - 10 cm 10 cm cm - 5 cm 93 B Part A: The electric potential on the x axis at x = 10 cm is, U2-10 cm = 2 + OP BP - +- - +- = (9x10° N.m²/C | (11x10-9C) (-13x10-9C) (-9x10°c) 11.18x10-2 m 10x10-m 11.18x10-2 m =(9x10° N·m²/C2)(0.984x10-7 -1.3x10-7 -0.805 x 10-7) =-1008.9 V Part B: From the figure, 10 cm 11.18 cm Cos=-

sin 5 cm = 11.18 cm = 0.45 The electric field at x = 10 cm is, Evo me (cosoi-sino j) bom the i-coso –sinej) = (2x10°N.m?/C) 11x10°C (0.89î -0.45 j) + (-13x10°C)i+ (-9x10° C) (-0.89î-0.451) (10x10m) (11.18x102 m) =(9x10° N-m?/C)(0.078x10° î–0.040x10° ſ-0.13x10° i0.064x10° î -0.032x10° j) =(9x10° N.m? /C°)(-0.116x10^ î-0.072x10-;) =(-10440 î–6480 j) NC The magnitude of the electric field at x = 10 cm is, Ex-10 cm = /(-10440)’ +(6480)? = 12287.55 N/C Part C: The electric potential at r=-10 cm is -1008.9 V Part D: The magnitude of the electric field at x=-10 cm is 12287.55 N/C.