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Предмет находится на расстоянии 90 см от линзы, а его изображение на расстоянии 30 см от линзы. Определить фокусное расстояние и оптическую силу линзы. Чему равно ее увеличение?
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Предмет:
Физика -
Автор:
buttercupkelley - 6 лет назад
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Ответы 1
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1/d+1/f=1/FF=d*f/(f+d)=90*30/(30+90)=22,5 смУвеличение Г=а.в=30.90=0,33
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Автор:
silly sallyfbwf - 2 года назад
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TEXT
BRITISH WEATHER
When British people want to feel proud of their climate, they say: “It’s marvellous: there’s so much variety. In the middle of winter we often have a lovely warm sunny day. The countryside is always changing.
There’s a lot of rain, of course, but that’s why the fields are so green.” But when they want to complain about the weather, they have different arguments. “You never know what to wear; the weather changes all the time. When you go on holiday, you have to take a warm coat, a scarf, an umbrella, wellingtons, sunglasses — you need three suitcases! Every time the weather changes you get a cold.”
There is one topic of conversation which never fails — the weather. Here is one aspect of it.
“The British seasons do not have much variation: it always seems to
rain — winter, spring, summer and autumn.
The winters can get quite cold in early January and sometimes we
may get a couple of inches of snow.
Spring is slightly warmer than winter but it continues to rain though you do get odd sunny days.
Summer can be dry but it never gets very hot. Autumn gets quite miserable as the trees lose their leaves, and it becomes cold and windy.”
Answer the questions:
1. Why do the English say they have weather not climate?
2. Do you think they are proud of it?
3. What do they say when they are disappointed in the weather?
4. What do you think of the pessimistic outlook on the English climate presented in the text?
5. Describe: a) winter and autumn in England, b) spring and summer.
6. Do you think the weather can make you feel miserable?
7. What kind of weather do you like?-
Предмет:
Английский язык -
Автор:
braeden139 - 6 лет назад
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Ответов:
3 -
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каркас теплицы изготовлен из металлических реек Найди общую длину всех реек каркаса
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Предмет:
Математика -
Автор:
shortyaklr - 6 лет назад
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Ответов:
1 -
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Поставьте глаголы в скобках в соответствующую временную форму: I (read) that book in my summer holidays. I (not see) him for three years. I (be glad) to see him again some time. What you (do)? I (copy) the text from the text-book now. He (go) to Moscow next week? When he (arrive)? – He (arrive) at two.
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Предмет:
Английский язык -
Автор:
gianterx0 - 6 лет назад
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Ответов:
1 -
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- Знайдіть перші чотири члени геометричної прогресії (bn) ,якщо b1=-2 , q=-3
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