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問題的種類

英文 高中

第四段第二行的pack是什麼意思? 解答寫「電池」但是我查不到pack有這個意思

第31至35 題為題組 Since the early 1990s, the hihilin zion battery has been the most suitable battery for portation to y 31 electronic equipment. Today, they're commonly used for cellphones, computers, tablets, digital cameras, and other devices. Lithium-ion batteries have nearly twice the energy density of traditional nicket cadmium batteries. 31 This feature has important implications for cellphones and computers, because it makes these items more portable for consumers. It also makes power tools easier to use and allows workers to use them for longer periods of time, 32. 32 Lithium-ion batteries retain retain mo naman of their power capacity from previous charging cycles. Thus they require no scheduled cycling and can be fully re-fueled to their maximum capacity during each charging cycle. Other rechargeable battery types, in contrast, retain information from previous charging cycles, which wastes valuable storage space. Over time, this makes these rechargeable batteries hold less of a charge. 33 It is fragile and requires a protection circuit to maintain safe operation. A high load could overheat the pack and safety might be jeopardized. 34 F After 2-3 years of use, the pack often becomes unserviceable due to a large voltage drop caused by high internal resistance. It should be noted, however, that manufacturers are constantly making improvements on lithium-ion batteries. 35 With such rapid progress, the use of lithium-ion batteries will certainly expand further. (A (A) The lithium-ion battery is also a low maintenance battery. (B) Despite its overall advantages, the lithium-ion battery has its drawbacks. (C) New and enhanced chemical combinations are introduced every six months or so. (D) Attempts to develop rechargeable lithium-ion batteries failed due to memory problems. (E) That is, they carry more power in a smaller unit, helping to reduce overall weight and size. d (F). Another downside is the increase of the internal resistance that occurs with cycling and aging. -3-

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自然科學 大學

求解圖裡UICK quiz的第二小題

acit0r 1taneOuls CUrTent Differentiating Equation 27.22 with respectto time gives the inst: as afunction of time: 4 tt號 一Fe ptasafurc 主二 where Q;/有CC 三方 is the initial current. Figure 27.15b 5 in the resistor that we guessedin order to-apply Kirch Equations 27.15 and 27.21. Equation 27.23 shows that the ci ing capacitor is negative, indicating that the current 1s Figure 27.15c. Both the charge on the capacitor and the ct tially at a rate characterized by the time'constant7了三用C. 人 i 一 GOuicK ouiz 27.5 Considerthe circuitin Figure 27.17 and assume the battery has after the switch is closed, what is the currentin the Figure 27.17 no internal resistance. () 」 battery (a) 0 (b) &/2A(G 28/Z04 8/元(e) impossible to determine (ii) After a 有 eyerylong time, what is the Currentin the battery? Choose from the same choices. theswitch is CC (3 前:銜1加信介2放 IntermittentWindshield Wipers nobiles are equipped with windshield wipers that can operate intermittently during alight rainfall. How does ofsuch wipers depend on the charging and discharging ofacapacitor7 民 The wipers are part ofan 及C circuit whose time constant can be varied by selecting different values of及through amultipo- Sition sWitch. As the voltage across the capacitor increases, the capacitor reaches a point at which it discharges and Higgers the wipers. The circuit then begins another charging cycle. The time interval between the individual sweeps of the wiperS 1 determinedjby the value ofthe time constant.

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