Problem 19.42 Two point charges lie on the 9: axis. A charge of + 2.40 pC is at the origin, and a charge of 4.50 pC is at a: = 12.0 cm. V PartA What third charge should be placed at a: = +26 cm so that the total electric field at an = +13.0 cm is zero? Express your answer to three significant figures and include appropriate units. Previous Answers Muest Answer ' X Incorrect; Try Again; 4attempts remaining ]