Bức Xạ Tử Ngoại Là Bức Xạ điện Từ | Cungthi.online

• Trang chủ
• Đề kiểm tra

Câu hỏi

Bức xạ tử ngoại là bức xạ điện từ A. mắt không nhìn thấy ở ngoài miền tím của quang phổ. B. có bước sóng lớn hơn bước sóng của bức xạ tím. C. không làm đen phim ảnh. D. có tần số thấp hơn so với bức xạ hồng ngoại. Đáp án và lời giải Đáp án:A

Bạn có muốn?

Xem thêm các đề thi trắc nghiệm khác

Xem thêm

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• 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 36 to 43.

  One of the seven wonders of the ancient world, the Great Pyramid of Giza was a monument of wisdom and prophecy built as a tomb for Pharaoh Cheops in 2720 B.C. Despite its antiquity, certain aspects of its construction makes it one of the truly wonders of the world. The thirteen- acre structure near the Nile river is a solid mass of stone blocks covered with limestone. Inside are the number of hidden passageways and the burial chamber of the Pharaoh. It is the largest single structure in the world. The four sides of the pyramid are aligned almost exactly on true north, south, east and west-an incredible engineering feat. The ancient Egyptians were sun worshippers and great astronomers, so computations for the Great Pyramid were based on astronomical observations.

  Explorations and detailed examinations of the base of the structure reveal many intersecting lines. Further scientific study indicates that these represent a type of timeline of events - past, present and future. Many of the events have been interpreted and found to coincide with known facts of the past. Others are prophesied for future generations and are currently under investigation. Many believe that pyramids have supernatural powers and this one is no exception. Some researchers even associate it with extraterrestrial beings of ancient past.

  Was this superstructure made by ordinary beings, or one built by a race far superior to any known today?

  On what did the ancient Egyptians base their calculations?

• Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 33 to 37.

  There has been an outbreak of avian influenza, better known as bird flu in Asia recently. The first (33) _____ died two weeks ago in Vietnam and there have been the cases reported since in Thailand, and there are some suspected cases in Cambodia as well as.

  Wild birds are affected by a large number of flu viruses, just as the humans and other animals are, but they are normally exclusive to birds. If the viruses manage to mutate, they can to jump the species barrier and infect human beings. The first case (34) _____ someone died was in Hong Kong in 1997.

  There are the several different forms of bird flu, ranging from mild to very (35) _____ infections, which spreading rapidly and kill many of the birds they infect. It is spread by wild birds-ducks, in particular – which carry the virus, but aren't killed by it. They can spread the virus to farm birds through (36) _____ contact or by the contaminating water supplies.

  World Health Organization officials have attributed the spread of bird flu to human contact with the droppings of infected birds and (37) _____ sanitation. There was no evidence at first that the virus spread from person to person, though there has been a case of this happening being investigated by scientists.

  Điền vào ô 36.

• Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

  Heavy rain makes driving on the road very difficult

• Mark the letter A,B,C or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

  He did not work hard. He failed the exam.

• Choose the best options to complete the following sentences.

  The teacher told me _________ the report card to my parents.

• Cho m gam glucozơ phản ứng hoàn toàn với lượng dư dung dịch AgNO3/NH3, đun nóng, thu được 21,6 gam Ag. Giá trị của m là

• Read the following pasage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

  As heart disease continues to be the number-one killer in the United States, researchers have become increasingly interested in identifying the potential risk factors that trigger heart attacks. High-fat diets and "life in the fast lane" have long been known to contribute to the high incidence of heart failure. But according to new studies, the list of risk factors may be significantly longer and quite surprising.

  Heart  failure,  for example, appears to have seasonal and temporal patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon in the mid-1980, and have since discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 A.M. and 10:00 A.M.

  In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered.

  The phrase “susceptible to” in the second paragraph could best be replaced by

• My sister is old. She can drive a car.

  My sister is old enough…………………………………………...

• The narrative in this book plays second fiddle to the excellent photographs.

• Phần tự luận

  Đặt tính rồi tính:

  187 953 + 246 435

CóKhông