Learning Goal: To understand the units of inductance, the potential energy stored in an inductor, and some of the consequences of having inductance in a circuit. After batteries, resistors, and capacitors, the most common elements in circuits are inductors. Inductors usually look like tightly wound coils of fine wire. Unlike capacitors, which produce a physical break in the circuit between the capacitor plates, the wire of an inductor provides an unbroken continuous path in which current can flow. When the current in a circuit is constant, an inductor acts essentially like a short circuit (i.e., a zero-resistance path). In reality, there is always at least a small amount of resistance in the windings of an inductor, a fact that is usually neglected in introductory discussions. Recall that current flowing through a wire generates a magnetic field in the vicinity of the wire. If the wire is coiled, such as in a solenoid or an inductor, the magnetic field is strongest within the coil parallel to its axis. The magnetic field associated with current flowing through an inductor takes time to create, and time to eliminate when the current is turned off. When the current changes, an EMF is generated in the inductor, according to Faraday's law, that opposes the change in current flow. Thus inductors provide electrical inertia to a circuit by reducing the rapidity of change in the current flow. Figure Graph A 3.5 $7 0.5 0 0.5 11.5 Graph C 3.5t 0.5 0 Time (ms) 051 15 2 Time (ms) Graph B 1st 0 Graph D ast 1.5 0.5 < 1 of 1 > 0.5 1 1.5 Time (m) 0.5 1 1.5 Time (ms) Electrical potential energy U is stored within an inductor in the form of a magnetic field when current is flowing through the inductor. In terms of the current I and the inductance L, the stored electrical potential energy is given by U = |LI². Part C Which of the following changes would increase the potential energy stored in an inductor by a factor of 5? Check all that apply. increasing the inductance by a factor of 5; leaving the current unchanged. leaving the inductance unchanged; increasing the current by a factor of 5 leaving the inductance unchanged; increasing the current by a factor of √5 reducing the inductance by a factor of 5; increasing the current by a factor of 5 increasing the inductance by a factor of 5; reducing the current by a factor of 5 Submit Previous Answers Request Answer X Incorrect; Try Again; 3 attempts remaining The figure shows 4 current versus time graphs, labeled A to D. Graph A is a descending concave As indicated by the equa upward curve, starting at 3 milliamps and converging inductor. If the current is zero at 1 millisecond and later. Graph B is an rate at which energy chai Energy cannot be deliver ascending concave downward curve, starting at the ously in the form of heat or light by other circuit elements. Thus power can never be infinite. This im origin and converging the limit of 2 milliamps from the aph is discontinuous when it contains a point at which the current jumps from one value to another with 1.5 milliseconds and later. Graph C is a polyline, equal ope of the curve at that location is infinite, which would imply infinite power in this case. to 3 milliamps from 0 to about 0.8 seconds, and then linearly descending to 2 milliamps at 2 milliseconds. Graph D consists of two straight lines, one from 1 milliamp at 0 seconds to 2.5 milliamps between 1 and about 1.25 milliseconds, and the other equal to 2 ▾ Part D ductor is related to the amount of electrical potential energy stored in the ate at which potential energy in the inductor is increasing or decreasing. The