A small 12.3-g plastic ball is tied to a very light 28.6-cm string that is attached to the vertical wall of a room (Fig. P21.73). A uni-form horizontal electric field exists in this room. When the ball has been given an excess charge of -1.11 μC, you observe that it remains suspended, with the string making an angle of 17.4° with the wall. Find the magnitude and direction of the electric field in the room.

Transcribed Image Text:

Figure P21.73 17.40