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物理 高校生

さんかっこでtが2~3のときPに対するQの電位が負となる時はないんですか?

基礎問 89 自己誘導起電力 自己インダクタンス2[H) のソレノイドコイル、 電流を制御できる電源,抵抗値 10 [2] の抵抗,内 部抵抗が無視できる電流計およびスイッチを図1に Q 示すようにつないで,同路をつくった。 電源を制御して回路に流れる電流を、図2のよう に時間変化させた。ただし、電源から点Pに向かう 電流を正とする。 (1) 時刻(0<t<1[s])のとき,ソレノイドコ イルに生じる誘導起電力の大きさを求めよ。 (2) 時刻t=0.5 [s] のときの電源の出力電圧 (両端の電圧)を求めよ。 ソレノイド ソレノイドコイルの誘導起電力の時間変化を,横軸を時刻tとして図示 抵抗 電源) 図1 電流I(A) 21 0 一時刻t() 図2 せよ。ただし、点Pに対して点Qの電位が高いときを正とする (東京電機大·広島大) ●自己誘導起電力 コイルに流れる電流が変化すると 精 講 を貫く磁束が変化することにより,コイルに誘導起電力があ。 する。これを自己誘導起電力といい、その大きさは電流の時間変化の如へ 4t に比例し、その比例定数Lを自己インダクタンスという。 自己誘導起電力:V=-L- dt 起電力の向き 電流の変化を妨げる向き ●相互誘導起電力 電流が変化するコイル(1次コイル)の近くに別のコイル(o 次コイル)があるとき,2次コイルを貫く磁束の変化により,2次コイルに発生 する誘導起電力カを相互誘導起電力という。誘導起電力の大きさは,1次コイル の電流の時間変化の割合号に比例し、その比例定数Mを相互インダクタンス という。 相互誘導起電力: V=-M dt

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英語 中学生

英語分かりません(´・ω・`) かぎかっこの中の問題です。 21から最後まで

(18) Theodore's computer, ( ) his mother gave him three years (23) A: John, are you interested in going to a kabuki performance ago, stopped working last night. 1where 2 how 3 which with me next weekend? 4 whose B: I don't know, Yuko. I've never seen kabuki before, ( A: You can get an English program. Ie'll tell you about the 23 ) (19) A: Have you heard the company is going to holda party for the story. employees next month? B: Yes, but I'm ( 1 around ) the plan. I think it's a waste of money. 4 against B: That would help. In that case, Id love to go with you. 2 Where is the theater? 4 Have you been before? 2 below 3 without 1 Is it expensive? 3 Will I understand it? (20) A: Have you seen Timothy? I need to talk to him. B: He's outside, ( 1 was talking 2 talking )on his cell phone. 3 talk (24) A: Hi, Tm Peter. You must be the new employee in the company. B: Yes. My name is Jordan. I just started working in the sales department. A: I work in the marketing department, across the hallway from you. ( 24 ) B: That would be nice. I don't know many places to eat around here yet. 4 talked 次の六つの会話文を完成させるために, (21) から (28) に入るものとして最も適切 2なものを 1, 2, 3, 4の中から一つ選び,その番号を解答用紙の所定欄にマーク しなさい。 (21) A: The TV news said it's going to rain later today. B: I know, but they're often wrong. They said that yesterday would be warm, ( A: Well, it must be hard to know what the weather is going to be. B: I guess so. But it would be nice if we could know for sure. 1 We should go out to lunch sometime. 2 Let me introduce you to my boss. 3 I'll show you where my department is. 4 You can use my office if you like. 21 ) A: Billy, do you have soccer practice this afternoon? B: Yeah, Mom. And I'm going to the library to get a book after that. A: ( 25 B: Practice ends at 5:30, so I think so. A: But the library closes at five o' clock on Sundays. B: Oh, no! ( 26 ) A: Well, I can go and get it for you while you're at practice. B: Really? Thanks a lot. I'Il tell you the title before I leave. 1 because it's raining now. 2 but it was actually quite cool. 3 and I watched the weather report. 4 since it's warm today. (22) A: Have you volunteered for that experiment the science professor is doing next Friday? B: Yes, I have. He's going just one hour! A: Wow, that's a lot of money. ( 22 ) B: I'm not sure, but I could ask the professor for you. pay people $50 to help him for (25) 1 Are you finished with your homework? 2 Are you sure you'll need a book? 3 Will you play soccer there? 4 Will you have time to go there? 1 Do you think I could doit, too? 2 Aren't you nervous about it? 3 Isn't that too much money? 4 How many days will it take? (26) 1 The book is too long for me. 2 The library won't have the book. 3 Ineed the book for my report. 4I forgot the title of the book. 16

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