Q29:The unit of magnetic flux is named for Wilhelm Weber. A practical-size unit of magnetic field is named for Johann Karl Friedrich Gauss. Along with their individual accomplishments, Weber and Gauss built a tele- graph in 1833 that consisted of a battery and switch, at one end of a transmission line 3 km long, operat- ing an electromagnet at the other end. Suppose their transmission line was as diagrammed in Figure P30.29. Two long, parallel wires, each having a mass per unit length of 40.0 g/m, are supported in a horizontal plane by strings , l= 6.00 cm long. When both wires carry the same current I, the wires repel each other so that the angle between the supporting strings is u = 16.08.
(a) Are the currents in the same direction or in oppo- site directions?
(b) Find the magnitude of the current.
(c) If this transmission line were taken to Mars, would the current required to separate the wires by the same angle be larger or smaller than that required on the Earth? Why?
pi =
g =
u =