Предмет:
Общая физика
Тема:
Ядерные реакции
Вопрос:

Через интервал времени, равный двум периодам полураспада, останется ____ % нераспавшихся радиоактивных ядер.

Ответы:
+ 25
− 50
− 75
− 0
Решение:
Период полураспада  это время, в течение которого первоначальное количество ядер данного радиоактивного вещества распадается наполовину. Через время, равное одному периоду полураспада, останется 50% нераспавшихся радиоактивных ядер, а еще через такой же промежуток времени – 25%.
ответ тест i-exam
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ARNOLD SCHWARZENEGGER
 I was born in a little Austrian town, outside Graz. When I was ten years old, I had the dream of being the best in the world in something. When I was fifteen, I had a dream that I wanted to be the best body 1 _____ in the world and the most muscular man. It took me some time of hard work. Five years later, I became Mr. Universe, the best-built man in the world.  I hold the record as Mr. Olympia, the top professional body-building championship. I 2 _____ it six times. That's why I retired. There was 3 ____ even close to me. Everybody gave up competing against me. When I was a small boy, my dream was not to be big physically, but big in way that everybody 4 ____ to me when I talk, that I’m a very 5 ____ person, that people recognize me and see me as something special.
I have emotions. But what you do, you keep them cold or you store them away for a time. Sport is one of those 6 ____ where you really have to concentrate. You have to 7 _____ at a very early date what you want: a normal life or to achieve things you want to achieve. I never wanted to win a popularity contest in doing things the way people want me to do it. I went the road I thought was best for me.
I believed very strongly in the philosophy of staying hungry. If you have a dream and it becomes a reality, don't stay 8 ____ with it too long. 9 ____ a new dream and hunt after that one and 10 _____ it into reality. When you have that dream achieved, make up a new dream.
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OUR FAIR LADY
Audrey Hepburn-Ruston was born in Brussels on May 4, 1929 in the family of a wealthy English banker and a Dutch baroness. Her parents divorced when she was six. Audrey's greatest love was music. She wanted to be a dancer, and she studied dancing since she was five. But one day the ballet school teacher 1 _____ her: ”I'm sorry, but you'll never be a famous dancer. You're too tall”. Then 2 _____ happened. It 3 _____ her life for ever. She was given a small part in a big London musical. The same year a Hollywood movie producer offered her the part of a princess in a big new movie, Roman Holiday. The film was a great 4 _____ and Audrey won an Oscar for Best Actress. She went on to star in a series of successful films and 5 ____ several Best Actress Oscar nominations for her performance. Not everybody considered her pretty, but most people 6 ____ that she had charm and class. Audrey starred in about 30 films. When she became older, she wanted to do something more important with her life. She started to work for the United Nations. She was officially 7 ____ UNICEF Goodwill Ambassador. She visited the poorest and most dangerous countries in the world. She died at the age of sixty four. Her face is still 8 ____ at us from posters and pages of fashion magazines. One of film critics said: “In this cruel and 9 ____ world Audrey was living proof that God could still 10 ____ perfection.”
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Why Are the British Mad about Harry?
Who has the most recognized face in Britain at the moment? No, it’s not the Queen, nor the Prime Minister, Tony Blair, it’s not even Robbie Williams! The most recognized face 1 _____ to a young man called Daniel Redcliffe. Although he is not generally known to the public 2 ____. Daniel Redcliffe. In fact, some people know his face as being that of. Harry Potter. Daniel Redcliffe is the actor who plays Harry Potter on film and whose face 3 _____ out from a thousand posters across the nation. The image of Harry Potter is so familiar that even people who haven’t read of the books or seen 4 ____of the films know exactly 5 ____ he is and exactly what he looks like.
The phenomenal success of JK Rowling’s Harry Potter books has been one of the most talked about. The big surprise has been how many children have been drawn to the books. The subsequent success of the films and merchandise that goes with them is far less 6 ____, but the fact 7 ____ thousands of children have actually read the original books has been seen as almost incredible. It 8 ____ to be said that many parents and teachers also have been impressed by the books of the Harry Potter series.
Since the 1960s Britain has seen a steady decline* in the 9 ____ of reading amongst school-age children and this has been blamed on television, films, computer games and excitingly presented magazines. The popularity of the Harry Potter series was seen so unusual that many newspaper and magazine articles were written about it to try 10 ______ its success.
*decline – спад, падение
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Why Are the British Mad about Harry?
Who has the most recognized face in Britain at the moment? No, it’s not the Queen, nor the Prime Minister, Tony Blair, it’s not even Robbie Williams! The most recognized face 1 _____ to a young man called Daniel Redcliffe. Although he is not generally known to the public 2 ____. Daniel Redcliffe. In fact, some people know his face as being that of. Harry Potter. Daniel Redcliffe is the actor who plays Harry Potter on film and whose face 3 _____ out from a thousand posters across the nation. The image of Harry Potter is so familiar that even people who haven’t read of the books or seen 4 ____of the films know exactly 5 ____ he is and exactly what he looks like.
The phenomenal success of JK Rowling’s Harry Potter books has been one of the most talked about. The big surprise has been how many children have been drawn to the books. The subsequent success of the films and merchandise that goes with them is far less 6 ____, but the fact 7 ____ thousands of children have actually read the original books has been seen as almost incredible. It 8 ____ to be said that many parents and teachers also have been impressed by the books of the Harry Potter series.
Since the 1960s Britain has seen a steady decline* in the 9 ____ of reading amongst school-age children and this has been blamed on television, films, computer games and excitingly presented magazines. The popularity of the Harry Potter series was seen so unusual that many newspaper and magazine articles were written about it to try 10 ______ its success.
*decline – спад, падение
Торговое предприятие владеет тремя магазинами (I, II и III), каждый из которых реализует периферийные компьютерные устройства: мониторы (М), принтеры (П), сканеры (С) или клавиатуры (К). На диаграмме 1 показано количество проданных товаров каждого вида за месяц. На диаграмме 2 показано, как за тот же период соотносятся продажи товаров (в штуках) в трех магазинах предприятия.
   
Какое из приведенных ниже утверждений следует из анализа обеих диаграмм?
А) Все сканеры могли быть проданы через магазин III.
Б) Все принтеры и сканеры могли быть проданы через магазин II.
В) Все мониторы могли быть проданы через магазин I.
Г) Ни один принтер не был продан через магазин II.

[Демовариант ФИПИ, 2011.]
Для проверки утверждения, что в химии от порядка смешивания реагентов зависит конечный состав продуктов реакции, провели два эксперимента. В первом эксперименте к 200 г 41,4 %-ного раствора карбоната калия постепенно при перемешивании добавили бромоводородную кислоту с массовой долей  24,3 %. В полученном растворе, содержащем три вида разных ионов, молярные концентрации солей, состоящих из этих ионов, оказались равны. Во втором эксперименте порядок смешивания тех же количеств растворов изменили на противоположный. Массовые доли (в %) веществ в конечных растворах, полученных в первом эксперименте равны ____ и ____, а во втором эксперименте ____и ____ соответственно. (Растворимостью углекислого газа в воде и процессами гидролиза пренебречь. Значения массовых долей округлять до сотых.)