年級

問題的種類

自然科學 大學

求解答案是否正確

Multiple-choice questions: (70 points) write the letter of statement that is not true: 1. A.B.U The Drude Model: (a) It is a classical approach using concepts from the kinetic theory of gases. (b) A relaxation-time approximation is used where the probability of collision is l/t. (c) No forces act on the electrons in between collisions. (d) It predicts accurately the electronic heat capacity of metals. 2. The Sommerfeld Model: (a) The crystal potential is replaced by an average Coulomb potential. (b) The separation of states is so close that a continuum model can be applied. (c) The electrons are highly localized due to a strong crystal potential. (Q) The energy of the highest occupied state at 0 K is the Fermi energy. 3. Density of states in k-space, N(k): (a) N(k) is determined by the boundary value conditions. (b) For lattices in any dimensions, N(k) is constant in k-space. (C) N(k) depends on the direction and magnitude of k. (d) It is directly proportional to the volume of the crystal. E影響, c 4. The Fermi surface of a metal: (a) is responsible for many of the transport properties of the metal, (b) depends on the nature of the chemical bonds, (c) is always a sphere, (d) can involve mixing of electron orbitals. ✓ 5. The conductivity of a material () increases with the mobility of its carriers, (b) increases with the density of carriers, (C) it is inversely proportional to the energy gap. cogu changes with temperature. 6. BID Plasmons: (a) They are an important characteristic of the Sommerfeld electron gas model. (b) Plasmons occur spontaneously in metals. (c) They are related to charge density oscillations. (d) The Plasmon energy is typically of the order of 10 eV. The Fermi energy Ef in intrinsic semiconductors 8) is usually close to y E, at OK (b) it ACiD. can increase or decrease with temperature depending on the ratio of hole and electron effective masses, (c) it represents the point at which the probability of occupation is 12, even though there may not been any states with that energy, (d) its value relative to the electronic bands must remain unaffected in the presence of defects or interfaces.

待回答 回答數: 0
英文 高中

這大題求解

... mer my friends III、綜合測驗:20% There are only a handful of underwater hotels around the world. These 16. guests to do what few people ever dream of doing: sleeping underwater. Fish, of course, do this all the time, but to humans the thought of 17... one's head on the seabed isn't very appealing. That's because mammals like us 18. have sufficient air to breathe. 19. _ ever wondered, therefore, how sea mammals, like whales, manage to get their beauty sleep? A number of 20. have attempted to answer this question. They seem to suggest that whales make use of an 21. sleep technique known as “logging." During "logging," whales are 22. to shut down just one half of their brains. This enables them to get some much-needed rest, and yet at the same time remain alert enough to regularly return to the surface of the water to breathe. 23. another sea creature that makes use of "logging" to survive is the dolphin. _ 24._ Whales, which can remain underwater for up to ninety minutes, dolphins need to breathe in fresh air above the surface every twenty minutes. Thus for them it's even more important to keep half their brains awake at all times. Logging helps them 25. this. At the end of the day, this is just another example of how human and animal sleep habits are different in strange yet wonderful ways. ( ) 16. (A) let (B) allow (C) make (D) have ( ) 17. (A) throwing (B) burying (C) laying (D) lying ( ) 18. (A) must (C) can (D) will ( ) 19. (A) Will you (B) Do you (C) Are you (D) Have you ( ) 20. (A) secrets (B) habits (C) studies (D) facts ( ) 21. (A) amazed (B) amazing (C) amaze (D) amazingly ( ) 22. (A) able (B) possible (C) capable (D) likely ( ) 23. (A) Just (B) SO (C) Also (D) Yet ( ) 24. (A) As (B) TO (C) With (D) Unlike ( ) 25. (A) achieving (B) achieve (C) be achieved (D) to achieving (B) may V. 文意選填:10%(請忽略大小寫) (A) in fact (B) however (C) amazing (D) standing (E) much Animals sleep in incredible ways. They don't need to lie in bed for hours like we do. Zebras an elephants, for example, can stay 26. while they sleep. This odd sleeping position sound uncomfortable, but it's 27. safer. Predators are always around to catch sleepy prey animals Elephants, therefore, are only away in dreamland for around 3.5 hours a day, Zebras are reported to slee even less. Giraffes, 28., sleep the least of any animal. An average of half an hour per day is usuall all they need to survive in the wild. 29. __, they hardly ever sleep for more than five minutes at a time That's simply 30. __! Can you imagine sleeping on your feet and for less than an hour a day? 6. 27. 28. 29. 30. . among Among Among fantasy novels, A song of favorite. my Ice and Fire is 在 入 267 A 面尚有試題) 6100182 Perguse

待回答 回答數: 0
數學 高中

這大題求解

II、綜合測驗:20% There are only a handful of underwater hotels around the world. These 16. guests to do what few people ever dream of doing: sleeping underwater. Fish, of course, do this all the time, but to humans the thought of 17._one's head on the seabed isn't very appealing. That's because mammals like us 18. have sufficient air to breathe. 19. _ ever wondered, therefore, how sea mammals, like whales, manage to get their beauty sleep? A number of 20. have attempted to answer this question. They seem to suggest that whales make use of an 21. sleep technique known as “logging.” During "logging," whales are 22. to shut down just one half of their brains. This enables them to get some much-needed rest, and yet at the same time remain alert enough to regularly return to the surface of the water to breathe. 23._ another sea creature that makes use of “logging" to survive is the dolphin. _24. Whales, which can remain underwater for up to ninety minutes, dolphins need to breathe in fresh air above the surface every twenty minutes. Thus for them it's even more important to keep half their brains awake at all times. Logging helps them 25. this. At the end of the day, this is just another example of how human and animal sleep habits are different in strange yet wonderful ways- ( ) 16. (A) let (B) allow (C) make (D) have ( ) 17. (A) throwing (B) burying (C) laying (D) lying ) 18. (A) must (B) may (C) can (D) will ( ) 19. (A) Will you (B) Do you (C) Are you (D) Have you ( ) 20. (A) secrets (B) habits (C) studies (D) facts ) 21. (A) amazed (B) amazing (C) amaze (D) amazingly ( ) 22. (A) able (B) possible (C) capable (D) likely ) 23. (A) Just (B) So (C) Also (D) Yet ) 24. (A) As (D) Unlike ) 25. (A) achieving (B) achieve (C) be achieved (D) to achieving (B) TO (C) With V. 文意選填:10%(請忽略大小寫) A) in fact (B) however (C) amazing (D) standing (E) much Animals sleep in incredible ways. They don't need to lie in bed for hours like we do. Zebra phants, for example, can stay 26. while they sleep. This odd sleeping position comfortable, but it's 27. safer. Predators are always around to catch sleepy prey a phants, therefore, are only away in dreamland for around 3.5 hours a day. Zebras are reported a less. Giraffes, 28. sleep the least of any animal. An average of half an hour per day is hey need to survive in the wild. 29. they hardly ever sleep for more than five minutes af fost and for less than an hour a day?

待回答 回答數: 0
數學與統計 大學

求第17題

人 14. Profit The profit 16. 人2/ 2 / Wcd/e Figure for 17 Figure for 18 18. 95 。Volume_AIl edgaes of a cube Pro hom selling x units Of a product ls glven by 2三 510N 0 atarate ot 9 units per dl the prottt when (am) 、 二 4 The sales are Jncreasing ay. Find the rate Of change Of 00 units and (bD)文三 600 unjts, qre expanding at a rate How fast is the volume changing when each edge is (a) 2 centimeters and (b) 10 centimeters? ot 6 centimeters per second, Surface Area_AI edges ofacube are expanding at a Tate of 6 centimeters Per Second. How fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters? 。 Boating_A boat is pulled by a winch on a dock, and te winch is 3 meters above the deck of the boat (See figure). The winch pulls_the Tope at arate of 1 meter per second. Find thexspeed 6fthe boat when 5 meters 9t Tope 1S out. What happens to the Speed of the boat as it gets closer and closer to the dock? Shadow Length “Aman 2meters tall walks at arate 0f ].5 meters per second away from a light that is 5 meters aboye the ground (see figure). | (a) When he js 3 meters from the base of the light, at 人 和 生0) what rate js the tip of his shadow moving。 (b) When he js 3 meters from the base of the at what rate js the Jength of his shadow changlng。 Air Traffic_Control An airplane flying at an altitude Of 10 kilometers pasSes directly over aradar 蟬戰品 品 figure). When the airplane is 26 kilometerS away ($ 三 26), 由 卅0 ee 21, 22 23 24 12 店

待回答 回答數: 0
英文 高中

請幫我看看哪個地方有錯 謝謝🙏

605. 66, 67< 68. 69. 70. 2 2 73. 7 252 ? 76, 2 8 2 )Inoticed Jasmine looking 80.( 8 82.( 583. ( ( (為 Thave learned that working hard is the most important key to suceess and 【 ) 一一 money for 1 TS 同 neW house, Ian works about ! (居)N osave_(D) Si en hours a day. seven ds AA told me 說 week AN Where was the 。SoTwent onmli was tain Statio ne and looked for the informatioi the train station i n_(B)howlcould get to 人 leeded ( We ne train Station一(&) which bus canltuu ) This letter do to getto the train station 及2 inFren, 。 (D) was written eneh. Teanytunderstand it一(A) writes (By is writing ( 寢 g (wot (吃 ) Manyvalus i) 》 Valuable anclent paintings in the Nat lpPal M generations to appreei 和 ie National Palace Museum forlater S to appreciate and (bb 誠 d Study (A) keep (B) are kept_(C) will keep_(D) to keep 全 to those who devote the 人人 te their lives to helping the needy ves (GB 全 S ving (C) has given (D) will be given 人 號拓 人 人7/ ) My room # i 》 m always S aa 滲購 Wlooks tidy because it by me almost every day. (A) is cleanine e (C) is cleaned (D) is to clean 滲 )The Great W: 、 at Wall by some aneient Chinese emperors to prevent attaceks from the north 頁 0 喉 )Holly doesm't know the TV remote control.”(作) where di put(B) where she 2 Put (GO where put she。(D) where she putting (1 _ on aroller coaster so far. Iwill neve pkS too scary.(A) have never ridden (B) have ever ridden (C) didn'tev ttwant to 人 必 ) James looked 區 when he knew that he had failed the math test once again.(A) Sadlv (B) sad (C) more sadly(D) sadness (愉 ) tisunwise people to spend so much time on online games. (A)of (B)tor (G) With_(D) as ( 人 ) Many areas in the city are flooded because it Taining (C) has been raining (D) was raining CA ) Can you recall ? (A) what happened to your little sister happen (S when did your mother cook the dinner(D) where you go this morning fora whole month. (AA) rains (By) (B)how did the event CA 了讓 捷 protect the environment, California imposed a ban on single-use plastic bags at large (A) Not in orderto(B) In ordernotto_(C) In orderthat_(D) Inorderto at Sam. She looked very atthe party.(A) happy; happy (B) happily; happily (C) happy; happily (D) hapbpily; happy retail stores in 2014. livinga simple life Will help me avoid poverty. (AA) What (B) whieh_(C) that_(D)x ) ITmissed Kevin's phone call yesterday, and lam wondering he called me for.(A) Why (B) what (C) when (D) 和hat 、_)江here has been nice weather So far this weekend spots and attractions are full oftourists enjoying their holidays. sueh; When(D) so; when ) The car was already ! country.(A) filled (B) filling_(C) being filled(D) being filling 2 Itis common for shooting Stars our planet"S atmosphere, but they usually burnu before striking the surface ofthe earth, (A) entering(B) for entering (C) to enter (D)to entering many famous Scen (A) such; that(B) so; that (( With gas, so We were ready to begin our road trip across the 四、文法選擇(其他考點)

尚未解決 回答數: 1