11. Calculate the sound intensity ratio (I drill/I conversation) for a pneumatic drill at 3 m (90 dB) compared to normal conversation at 1 m (60 dB).g

15. The magnitude of the electric field between the two circular parallel plates in the figure is E = (4.0 × 105) - (6.0 x 104t), with E in volts per meter and t in seconds. At t = 0, is upward. The plate area is 6.0 x 10-2 m². For t≥ 0, what is the magnitude of the displacement current between the plates?