A 60-Hz, 230-mile, three-phase overhead transmission line has a series impedance z = 0.8431 ∠79.04° Ω/mi and a shunt admittance y = 5.105 × 10-6 ∠90° S/mi. The load at the receiving end is 125 MW at unity power factor and at 215 kV. Determine the voltage, current, and both real and reactive power at the sending end and the percent voltage regulation of the line. Also, find the wavelength and velocity of propagation of the line.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.