Texts: Describe the solution process in detail.
9. [20 pt=6+2+5+1+3+3] Consider a long infinite straight wire carrying a current i as shown in Figure 9a). Applying the law of Biot-Savart, find the (a) magnitude of the magnetic field at point P, a perpendicular distance R from the wire. [Hint: dx]
(b) Determine the direction (into the plane/out of the plane) of the magnetic field at P. Consider an ideal solenoid which is infinitely long and consists of tightly packed turns of wire as shown in Figure 9(b). Let be the number of turns per unit length of the solenoid. (c) Applying Ampere's law, find the magnitude of the magnetic field inside the solenoid carrying current i. (d) Determine the direction of the magnetic field inside the solenoid (right or left along the solenoid axis). A long solenoid with n number of turns per unit length and radius R carries a current of i, as shown in Figure 9(c). A current of i exists in a straight conductor located along the central axis of the solenoid. (e) Find the radial distance from the axis at which the direction of the magnetic field is 45° to the axial direction in terms of i and n. Is it possible to have 45° to the axial direction if 2TtnR? Explain.
(a)
(b)
(c)
Figure 9
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