Question

17. A parallel-plate, air-filled capacitor is being charged as in the Figure below The circular plates have radius 4.00 cm, and at a particular instant, the conduction current in the wires is o.720 A. Recall that the conduction current for the flat surface is equal to the displacement current for the curved bulging surface. Using Ampere's law, the magnitude of the magnetic field at point a distant by r 1 cm from the horizontal axis of two plates is: (5 pts) (a) 2.7 x 10-6T b) 9.0 × 10-7 T (c) 1.7 x 10-7T 18. A uniform rectangular coil of total mass 270 g and dimensions 0.500m times 1.00m is oriented parallel to a uniform 3.60-T magnetic field (see Figure below).A current of 2.60 A is suddenly started in the coil, and the coil starts rotating about the A2 axis. Use the rotation form of Newton's second law to find the initial angular acceleration ? of the coil just after the current is started. To find the moment of inertia of the coil, treat the two 1.00-m segments as point-masses (since all the points in them are 0.250 m from the rotation axis) and the two 0.500-m segments as thin uniform bars rotated about their centers (5 pts) 0.500 1.0pm a) 356.4 rad/s2 b) 181.5 rad/s2 c)92.2 rad/s e)-181.5 rad/s2 Page 6 of 11