Câu hỏi:
11/04/2020 947Read the passage and mark the letter A, B, C or D to answer the following questions.
Most sources of illumination generate light over an appreciable period, and indeed if an object is lit for a very brief time (1ess that 1/25 second), the human eye will not react in time to see the object. A photographic emulsion - that is, a light-sensitive coating on photographic film, paper, or glass - will, however, record much shorter bursts of light. A photographic flash can therefore be used to capture high-speed movement on film as well as to correct deficiencies of the normal surrounding lighting. Photoflash is now generated electronically, but the earliest form, first used in 1864, was a paper bag containing
magnesium wire and some oxygen-rich substance, such as potassium chlorate. When the bag was ignited, the metal burned with an intense flash. A contemporary observer reported that "this quite unsafe device seems to have done nothing worse that engulf the room in dense smoke and lead to pictures of dubious quality and odd poses.”
The evolution of the photoflash was slow, flashbulbs, containing fine wire made of a metal, such as magnesium or aluminum, capable of being ignited in an atmosphere of pure oxygen at low pressure, were introduced only in the 1920's. In the earliest type, the metal was separated from the oxygen by a thin glass bulb. The flash was fired by piercing the bulb and allowing the oxygen to come into contact with the metal, which ignited spontaneously. Later bulbs were fired by an electric battery, which heated the wire by passing a small current through it. Other combinations, such as the pairing of oxygen difluoride with zirconium, have also been used. In each case enough energy is given out to heat the oxidizable metal momentarily to a white hot emission of visible light. The smoke particles are so small that they cool rapidly; but since they are white, they contribute to the brilliance by reflecting the light from their still glowing neighbors. A slightly bigger form of the metal will burn for a longer time.
The word "ignited" in paragraph 1 is closest in meaning to ______.
Sách mới 2k7: Tổng ôn Toán, Lí, Hóa, Văn, Sử, Địa…. kỳ thi tốt nghiệp THPT Quốc gia 2025, đánh giá năng lực (chỉ từ 110k).
Quảng cáo
Trả lời:
Đáp án A
Từ "ignited” trong đoạn 1 gần nghĩa nhất với __________.
A. đốt cháy B. cắt C. mở D. rung
Căn cứ vào thông tin đoạn 1:
Tạm dịch: “When the bag was ignited, the metal burned with an intense flash." (Khi chiếc túi được đánh lửa, kim loại bị đốt cháy với ánh sáng dữ dội.)
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Local authorities should find ways to limit the use of private cars and encourage city _____ to use public transport.
Câu 2:
_____ the email - supposedly from Boyd's Bank - to be genuine, she was tricked into disclosing her credit card details.
Câu 3:
This safe, _____ friendly city is like a paradise for its inhabitants who can enjoy the highest quality of life.
Câu 4:
Mark the letter A, B, C, or D to indicate the word(s) CLOSEST in meaning to the underlined word (5) in each of the following questions.
Young college and university students participate in helping the poor who have suffered badly in wars or natural disasters.
Câu 5:
My brother has applied for that scholarship for months, but he has never succeeded yet.
Câu 6:
Mark the letter A, B, C, or D to indicate the word(s) CLOSEST in meaning to the underlined word (5) in each of the following questions.
Life expectancy for both men and women has improved greatly in the past twenty years.
Câu 7:
When I got to 16, some of my friends left school to get a job, but most _____.
về câu hỏi!