question_answer 49)

  A long straight wire carrying current of 25 A rests on a table as shown in Fig. 3(EP).4. Another wire PQ of length 1 m, mass 2.5 g carries the same current but in the opposite direction. The wire PQ is free to slide up and down. To what height will PQ rise?

Answer:

                  Here, m = 2.5 g = 2.5 X kg In equilibrium position                                                      or