An insulating circular ring of radius b lies in the xy plane, centered at the origin. It carries a linear charge density λ(φ) = λ0 sin φ, where λ0 is a constant and φ is the usual azimuthal angle. The ring is now set spinning at a constant angular velocity ω around the z axis. Calculate the power radiated.

Hydroelectricity provides about 7 percent of the electricity generated in the united states. (a) explain how a hydroelectric power plant converts energy stored in water into electricity. (b) identify two factors that determine the amount of electricity that can be generated by an individual hydroelectricity power plant. (c) describe the two main types of land-based hydroelectric power plants. (d) describe two economic advantages and two environmental disadvantages of hydroelectricity.