onsider the figures below. a) Derive an expression for the force per unit length between two parallel conductors of equal lengths, carrying currents directed in the opposite direction (See figure a). b) Two parallel conductors carrying equal currents directed in the opposite direction are supported by 10-cm strings as shown on figure b. The angle between the strings is caused by the magnetic forces that the conductors act on each other. If the two conductors have equal lengths and have a mass per unit length of 1.5 g/cm, determine the magnitude of the current to keep the angle between the strings at 20°.

onsider the figures below. a) Derive an expression for the force per unit length between two parallel conductors of equal lengths, carrying currents directed in the opposite direction (See figure a). b) Two parallel conductors carrying equal currents directed in the opposite direction are supported by 10-cm strings as shown on figure b. The angle between the strings is caused by the magnetic forces that the conductors act on each other. If the two conductors have equal lengths and have a mass per unit length of 1.5 g/cm, determine the magnitude of the current to keep the angle between the strings at 20°.