Chapter 21, Problem 30P

(II) A long uniformly charged thread (linear charge density λ = 2.5 C/m) lies along the x axis in Fig. 21–56. A small charged sphere (Q = −2.0 C) is at the point x = 0 cm, у = −5.0 cm. What is the electric field at the point x = 7.0 cm, у = 7.0 cm? ${\stackrel{\to }{E}}_{\text{thread}}$ and ${\stackrel{\to }{E}}_{\text{Q}}$ represent fields due to the long thread and the charge Q, respectively.

FIGURE 21–56

Рroblem 31.