A uniform magnetic field fills a cylindrical volume of radius R, and the field magnitude changes with time at an unknown rate. At a certain instant, the electric field magnitude at a radial distance r1< R from the magnetic field center is E1. At this instant, at what radial distance r from the magnetic field is the electric field magnitude E equal to E1/3 (a) if r < R or (b) r = R?

Atennis player used a tennis racket to hit a tennis ball with a mass of 0.25 kg with a force of 5.25 newtons. how does the force the tennis racket exerted on the tennis ball compare with the force the tennis ball exerted on the tennis racket? a. the force of the tennis racket on the tennis ball is equal in magnitude and opposite in direction to the force the tennis ball exerted on the tennis racket. b. the force of the tennis racket on the tennis ball is equal in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. c. the force of the tennis racket on the tennis ball is less in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. d. the force of the tennis racket on the tennis ball is greater in magnitude and opposite in direction as the force the tennis ball exerted on the tennis racket.