Figure 1 of 1 Graph A Current (mA) 3.5 3525-5 1.5 0.5 Graph B 3.5 Current (mA) 2.5 332578 1.5 0.5 < > 0 0.5 1 1.5 2' 0 Time (ms) 0.5 1 1.5 Time (ms) 2 Graph C Graph D 3.5 3.5 Current (mA) 3 2.5 2 1.5 Current (mA) 3 2.5 2 1.5 1 0.5 0.5 0 0.5 1 1.5 2' Time (ms) 0 0.5 1 1.5 2 Time (ms) Inductance is usually denoted by L and is measured in SI units of henries (also written henrys, and abbreviated H), named after Joseph Henry, a contemporary of Michael Faraday. The EMF & produced in a coil with inductance Lis, according to Faraday's law, given by E=-LAI At Here AI/At characterizes the rate at which the current I through the inductor is changing with time t. Part A Based on the equation given in the introduction, what are the units of inductance L in terms of the units of E, t, and I (respectively volts V, seconds s, and amperes A)? 1 H 1 (V s A) 1 H=1 . (V.) A 1 H=1 ( (V.A) 1 H=1 (SA) 1 H=1 ( 1 V.s.A Submit My Answers Give Up Part B What EMF is produced if a waffle iron that draws 2.5 amperes and has an inductance of 560 millihenries is suddenly unplugged, so the current drops to essentially zero in 0.015 seconds? Express your answer in volts to two significant figures. ΕΠΙ ΑΣΦ ? V Submit My Answers Give Up 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 My Answers Give Up As indicated by the equation in the introduction to this part, the current flowing through an inductor is related to the amount of electrical potential energy stored in the inductor. If the current is graphed as a function of time, the slope of the curve indicates the rate at which potential energy in the inductor is increasing or decreasing. The rate at which energy changes over time is known as power. Energy cannot be delivered to the inductor infinitely fast, nor can it be dissipated instantaneously in the form of heat or light by other circuit elements. Thus power can never be infinite. This implies that the curve of current versus time must be continuous. A graph is discontinuous when it contains a point at which the current jumps from one value to another without taking on all the values in between. When this happens, the slope of the curve at that location is infinite, which would imply infinite power in this case. Part D Which of the graphs illustrate how the current through an inductor might possibly change over time? (Figure 1) Type the numbers corresponding to the right answers in alphabetical order. Do not use commas. For instance, if you think that only graphs C and D are correct, type CD. Submit My Answers Give Up Provide Feedback Continue