IMG-LOGO

Câu hỏi:

22/07/2024 645

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significantly greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperatures were too high and particles of matter were moving around much too rapidly. It was only after the one- minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased

The creation of helium within stars____________.

cannot be measured

produces hydrogen as a by-product

produces energy

Đáp án chính xác

causes helium to be much more abundant in old stars than in young stars

 Xem lời giải

Trả lời:

verified Giải bởi Vietjack

Question 49. Đáp án C

Dịch đề bài: Sự tạo thành Heli ở các ngôi sao____________           

A. không thể đo lường được

B. sinh ra Hydro như một sản phẩm phụ

C. sinh ra năng lượng

D. khiến Heli trở nên dồi dào hơn nhiều ở các ngôi sao già so với các ngôi sao trẻ

Câu hỏi lấy thông tin. Hướng dẫn làm bài có ở câu 44.

Trích thông tin bài: “Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce.”

Tạm dịch: Heli được tạo ở các ngôi sao. Trong thực tế, các phản ứng hạt nhân chuyển Hydro thành Heli chịu trách nhiệm sinh ra phần lớn năng lượng mà các ngôi sao sinh ra. → phản ứng chuyển Hydro thành Heli sinh ra phần lớn năng lượng của các ngôi sao.

Vậy, đáp án C là phù hợp.

Câu trả lời này có hữu ích không?

0

Gói VIP thi online tại VietJack (chỉ 400k/1 năm học), luyện tập gần 1 triệu câu hỏi có đáp án chi tiết

ĐĂNG KÝ VIP

CÂU HỎI HOT CÙNG CHỦ ĐỀ

Câu 1:

The company managed to beat the ____________on delivering its new system.

Xem đáp án » 16/11/2021 11,873

Câu 2:

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

Keith had so interesting and creative plans that everyone wanted to work on his committee.

Xem đáp án » 16/11/2021 8,256

Câu 3:

Everyone thought she would accept the offer. ____________, she turned it down immediately.

Xem đáp án » 16/11/2021 7,728

Câu 4:

There is still widespread____________against older people in the job market.

Xem đáp án » 16/11/2021 7,389

Câu 5:

It was hard to____________the temptation to watch the late-night show even though I was so tired then.

Xem đáp án » 16/11/2021 7,234

Câu 6:

I don’t know much about computer, so I asked the assistant for____________advice.

Xem đáp án » 16/11/2021 6,961

Câu 7:

I ran in a marathon last week, but I was not fit enough. I____________after 15 kilometres.

Xem đáp án » 16/11/2021 6,653

Câu 8:

The children were made____________up the mess they had left before they could watch TV.

Xem đáp án » 16/11/2021 6,168

Câu 9:

You should know that everyone in this office____________busy planning the dance for a week.

Xem đáp án » 16/11/2021 6,028

Câu 10:

Women have proved repeatedly that they are equal and often superior____________men in almost every field.

Xem đáp án » 16/11/2021 3,441

Câu 11:

I wish I____________able to accept that role, but I was preparing for another play at the time.

Xem đáp án » 16/11/2021 3,156

Câu 12:

Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.

Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (35) ____________to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities.

Xem đáp án » 16/11/2021 2,663

Câu 13:

I would have cooked something special if I____________you were coming.

Xem đáp án » 16/11/2021 2,391

Câu 14:

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.

Mark and Anne are talking after the class.

Mark: “Guess what? I’ve been recruited to be a member of Green Dream Volunteer Group.”

Anne: “____________”

Xem đáp án » 16/11/2021 2,111

Câu 15:

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

Air pollution, together with littering, are causing many problems in our large, industrial world.

Xem đáp án » 16/11/2021 2,109

Câu hỏi mới nhất

Xem thêm »
Xem thêm »