Вопрос школьника по предмету Физика
Чему равно сопротивление медной проволоки длиной 25 м и площадью поперечного сечения 1 мм2?
Ответ учителя по предмету Физика
po=0.017 Ом*мм2/м L=25 м S=1 мм2 R=?
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R=po*L/S=0.017*25/1=0.425 Ом
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Ex. 4. Choose the correct verb to express a modal meaning.
7. He … speak three foreign languages.
a) can; b) may; c) must
8. You … work hard at your English if you want to know it.
a) can; b) may; c) must
9. You … not go out, the lesson is not over yet.
a) can; b) may; c) have
10. He … be in this room.
a) must; b) is; c) has
11. Must I come tomorrow? – No, you … .
a) mustn’t; b) can’t; needn’t
12. May I invite my friend to the party? – Yes, you … .
a) can; b) may; c) must
7. You feel bad, you … see a doctor.
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8. I … walk, there is a bus going there.
a) needn’t; b) mustn’t; c) can’t