7. As current travels within a conductor, A. the magnetic field aids the current
B. a magnetic field is developed around it
C. the wire tries to point north
D. an electrostatic field opposes the current​

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?