Homework Solutions for Phsx 2220 - Magnetic Fields, Capacitors, and Inductors, Assignments of Physics

Download Homework Solutions for Phsx 2220 - Magnetic Fields, Capacitors, and Inductors and more Assignments Physics in PDF only on Docsity! Phsx 2220 - Homework #8 32-1. The magnetic field of Earth can be approximated as the magnetic field of a dipole, with horizontal and vertical components, at a point a distance r from Earth’s center, given by where λm is the magnetic latitude (latitude measured from the geomagnetic equator toward the north or south geomagnetic pole.) Assume that Earth’s magnetic dipole moment is µ = 8.00 x 1022 A.m2. Find the magnitude and inclination of Earth’s magnetic field (the angle the magnetic field makes with the horizontal) at (a) the geomagnetic equator; (b) a point at geomagnetic latitude 60o; (c) the north geomagnetic pole. 32-2. Measurements in mines and boreholes indicate that Earth’s interior temperature increases with depth at the average rate of 30 oC/km. Assuming a surface temperature of 10 oC, at what depth does iron cease to be ferromagnetic? (The Curie temperature of iron varies very little with pressure.) 32-3. The induced magnetic field 6.0 mm from the central axis of a circular parallel-plate capacitor and between the plates is 2.0 x 10-7 T. The plates have radius 3.0 mm. At what rate dE/dt is the electric field between the plates changing? 32-4. At what rate must the potential difference between the plates of a parallel-plate capacitor with a 2.0 µF capacitance be changed to produce a displacement current of 1.5 A? 32-5. The magnitude of the electric field between the two circular plates of the parallel-plate capacitor shown at right is E = (4.0 x 105) - (6.0 x 104 t), with E in volts per meter and t in seconds. At t = 0, the field is upward as shown. The plate area is 4.0 x 10-2 m2. For t > 0, (a) what are the magnitude and direction of the displacement current between the plates and (b) is the direction of the induced magnetic field clockwise or counter-clockwise around the plates? 33-6. A 1.5 µF capacitor is connected as shown at right to an ac generator with Em = 30.0 V. What is the amplitude of the resulting alternating current if the frequency of the emf is (a) 1.00 kHz and (b) 8.00 kHz?