Chapter 4: Q80CP (page 953)
A wide, long, insulating belt has a uniform positive charge per unit area s on its upper surface. Rollers at each end move the belt to the right at a constant speed v. Calculate the magnitude and direction of the magnetic field produced by the moving belt at a point just above its surface. (Hint:At points near the surface and far from its edges or ends, the moving belt can be considered to be an infinite current sheet like that in Problem 28.73.)
Short Answer
The magnitude of the magnetic field is and the direction is outside the page.