单选题Sound is audible to human beings only if the frequency is______.A fewer than about 20 vibrations per secondB more than about 20,000 vibrations per secondC about in a range of 20 to 20,000 vibrations per secondD 120 vibrations per second

题目
单选题
Sound is audible to human beings only if the frequency is______.
A

fewer than about 20 vibrations per second

B

more than about 20,000 vibrations per second

C

about in a range of 20 to 20,000 vibrations per second

D

120 vibrations per second

相似考题

1.数字带宽的单位是什么()。A.bytes per secondB.bits per secondC.Megabits per secondD.Centimeters

2.Which two statements are true about setting the per－thread buffers higher than required?()A.More memory per thread is beneficial in all scenariosB.It causes increased overhead due to initial memory allocationC.It can affect system stability during peak load times, due to swappingD.It requires increasing the thread_cache_size variable

3.传送速率单位“bps”代表的意义是(29)；路由器是(30)层的设备；IP地址共有5类，常用的有(31)类，其余留作其他用途；虚拟网可以有多种划分方式，下列方式中不正确的是(32)；100Base-T使用(33)作为传输介质。A．Bytes per SecondB．Bits per SecondC．Baud per SecondD．Billion per Second

4.传送速率单位“b/s”代表( ) 。A.bytes per secondB.billion per secondC.baud per secondD.bits per second

参考答案和解析
正确答案： D
解析：
细节题。文章第二段倒数第二句提到“The human ear is usually not sensitive to frequencies of fewer than 20 vibrations per second, or more than about 20,000 vibrations per second”，即“人的耳朵对每秒震动20次以下或2万次以上的声音不敏感”，因此C项正确。
更多“单选题Sound is audible to human beings only if the frequency is______.A fewer than about 20 vibrations per secondB more than about 20,000 vibrations per secondC about in a range of 20 to 20,000 vibrations per secondD 120 vibrations per second”相关问题

  • 第1题：

    数据通信中关于信道传输速率单位是比特率（bps）的含义是（ ）。

    A． Bits per second

    B． Bytes per second

    C． Baud per second

    D． Billion per second


    正确答案：A

  • 第2题：

    Rainfall in most of the Sahara is________.

    A) less than five inches per year
    B) less than ten inches per year
    C) less than twenty inches per year
    D) zero

    答案：B
    解析：

  • 第3题：

    When monitoring a system using /usr/bin/vmstat with an interval， the metrics under page pi and page po represent which of the following phrases？（）

    • A、 The pages to and from paging space per second
    • B、 The page intervals and page operations per second
    • C、 The page interrupts and page operations per second
    • D、 The page segments transferred between pi and po devices per second

    正确答案:A

  • 第4题：

    One hertz is equal to one ( )

    • A、cycle per centimeter
    • B、cycle per meter
    • C、cycle per second
    • D、cycle per eV

    正确答案:C

  • 第5题：

    传送速度单位“bps”的含义是（）。

    • A、bytes per second
    • B、bits per second
    • C、baud per second
    • D、billion bytes per second

    正确答案:B

  • 第6题：

    我们通常所说的100Mbps，bps为传送速率，其含义为（）

    • A、Bytes Per Second
    • B、Bits Per Second
    • C、Baud Per Second
    • D、Billion Per Second

    正确答案:B

  • 第7题：

    数字带宽的单位是什么（）。

    • A、bytes per second
    • B、bits per second
    • C、Megabits per second
    • D、Centimeters

    正确答案:B

  • 第8题：

    单选题
    When administering artificial respiration to an adult, the breathing cycle should be repeated about （）
    A

    12 to 15 times per minute

    B

    18 to 20 times per minute

    C

    20 to 25 times per minute

    D

    as fast as possible


    正确答案： D
    解析： 暂无解析

  • 第9题：

    单选题
    With one or more cylinders out of operation, the engine speed must be reduced because（）
    A

    in such cases, the air supply is no longer optimal, the thermal load will be higher

    B

    governor hunting will occur

    C

    torsional vibrations as other mechanical vibrations may occur

    D

    all of the above are correct


    正确答案： A
    解析： 暂无解析

  • 第10题：

    单选题
    Which statement is true about the frequency of OSPF LSA transmissions？（）
    A

     They are configured per OSPF area.

    B

     They are configured per virtual router.

    C

     They are configured per OSPF process.

    D

     They are configured per OSPF interface.


    正确答案： B
    解析： 暂无解析

  • 第11题：

    填空题
    On Mindy's guitar, the frequency of a vibrating string varies inversely as the length of the string. When a guitar string of s inches in length that vibrates at a frequency of 80 cycles per second is shortened to 6 inches in length, it vibrates at a frequency of 120 cycles per second. What is the value of s?____

    正确答案： 9
    解析：
    根据题干可列出等式alb1＝a2b2，(s)(80)＝(6)(120)，s=9。

  • 第12题：

    单选题
    The governor brake shall be capable of controlling the speed of lowering a fully equipped lifeboat with its complement of persons on board at（）.
    A

    safe speed only specified

    B

    not less than 120 feet per minute

    C

    not more than 120 feet per minute

    D

    not more than 90 feet per minute


    正确答案： A
    解析： 暂无解析

  • 第13题：

    The governor brake shall be capable of controlling the speed of lowering a fully equipped lifeboat with its complement of persons on board at ______．

    A.safe speed only specified

    B.not less than 120 feet per minute

    C.not more than 120 feet per minute

    D.not more than 90 feet per minute


    正确答案：C

  • 第14题：

    共用题干
    Obesity（肥胖）in the Western World
    Obesity is rapidly becoming a new problem of the western world,delegates agreed at the 1 1 th European Conference on the issue in Vienna Wednesday to Saturday.According to statements before the opening of the conference-of 2,000 specialists from more than 50 countries-1.2 billion people worldwide are overweight, and 250 million are obese.
    Professor Bernhard Ludvik of Vienna General Hospital said:"Obesity is a chronic illness.In Germany, 20 per cent of the people are already affected,but in Japan only one per cent."But he said that there was hope for sufferers thanks to the new scientific discoveries and medication.
    Professor Friedrich Hopichier of Salzberg said:"We are living in the new age(but)with the metabolism （新陈代谢）of a stone-age man."" I have just been to the United States.It is really terrible.A pizza shop is spnnglng up on every corner.We have been overrun by fast food and Coca-Cola-ization."
    Many of the experts stressed that obesity was a potential killer.Hopichier said:"Eighty percent of all diabetics are obese,also fifty per cent of all patients with high blood pressure and fifty per cent with adipose （脂肪的）tissue complaints." " Ten per cent more weight means thirteen per cent more risk of heart disease. Reducing one's weight by ten per cent leads to thirteen per cent lower blood pressure."
    Another expert Hermann Toplak said that the state health services should improve their financing of preventive programs."Though the health insurance pays for surgery(such as reducing the size of the stomach) when the bodymass index is more than 40.That is equivalent to a weight of 1 1 6 kilograms for a height of 1.70 meters.One should start earlier."
    Ludvik said that prevention shoald begin in school."Child obesity(fat deposits)correlates（与……相关）with the time which children spend in front of TV sets."
    The consequences were only apparent later on.No more than fifteen per cent of obese people lived to the average life expectancy for their population group.

    Which of the following is true about obesity in Paragraph 2?
    A:People in Japan needn't worry about obesity.
    B:Obesity is a disease that lasts for a long time.
    C:20%of the people in the world are overweight.
    D:Obesity should be cured with new medication.

    答案：B
    解析：
    由第二段内容可知，日本仅有1%的人患有肥胖症，但并未提到日本的民众不用担心肥胖症，故A项错误。同样，德国有20%的人患有肥胖症，而不是说全球，故C项错误。又由该段最后一句可知，新的科学发现以及新的药物给肥胖症患者带来了希望，而并未说肥胖症就应该用新的药物治疗，故D项错误。文章第二段中提到，肥胖症是一种慢性病。故B项正确：
    由文章第四段第二句可知，Hopichier教授说80%的糖尿病患者都患有肥胖症，但并未说糖尿病主要是由肥胖症引起的，故可排除A项。又根据此句后半句可知，有50%的糖尿病患者血压高，而不是说50%的高血压患者抱怨肥胖，故又可排除B项。同时，文中只是说美国的披萨店到处可见，并未说其提供的快餐不可口，故又可排除C项。又由文章第四段第三句可知，该教授认为：体重每增加10%，心脏病发生的几率将会增加13%。故本题选D。
    由文章第五段第一句可知，该名专家认为，公共医疗卫生服务应该提高对预防机制的投资，故选B。
    由文章第四段第二句话可知，80%的糖尿病人是肥胖者，故选A。
    consequence是含义为“后果，结果”。文章后半部分都在讲各方面专家所给出的减肥建议，倒数第二段更是提出防止肥胖要从孩子抓起。"Ludviksaidthatpreventionshouldbegininschool.""Childobesity(fatdeposits)correlates（与……相关）withthetimewhichchildrenspendinfrontofTVsets.”但减肥的效果如何，人们只能拭目以待。所以根据逻辑关系，应该选A。

  • 第15题：

    Which statement is true about the frequency of OSPF LSA transmissions？（）

    • A、 They are configured per OSPF area.
    • B、 They are configured per virtual router.
    • C、 They are configured per OSPF process.
    • D、 They are configured per OSPF interface.

    正确答案:D

  • 第16题：

    传送速率单位“b/s”代表（）即“bps”比特率。

    • A、bytes per second
    • B、bits per second
    • C、baud per second
    • D、billion per second

    正确答案:B

  • 第17题：

    传送速率单位“bps”代表（）

    • A、Bytes Per Second
    • B、Bits Per Second
    • C、Baud Per Second
    • D、Billion Per Second

    正确答案:B

  • 第18题：

    计算机通信中数据传输速率单位bps代表（）。

    • A、 band per second
    • B、 billion per second
    • C、 bytes per second
    • D、bits per second

    正确答案:D

  • 第19题：

    Which two statements are true about setting the per-thread buffers higher than required?（）

    • A、More memory per thread is beneficial in all scenarios
    • B、It causes increased overhead due to initial memory allocation
    • C、It can affect system stability during peak load times, due to swapping
    • D、It requires increasing the thread_cache_size variable

    正确答案:B,C

  • 第20题：

    单选题
    When monitoring a system using /usr/bin/vmstat with an interval， the metrics under page pi and page po represent which of the following phrases？（）
    A

     The pages to and from paging space per second

    B

     The page intervals and page operations per second

    C

     The page interrupts and page operations per second

    D

     The page segments transferred between pi and po devices per second


    正确答案： B
    解析： 暂无解析

  • 第21题：

    单选题
    The max effluent of the oil content from a ship of 400 tons gross tonnage and above other than an oil tanker is（）.
    A

    less than 100 parts per million

    B

    more than 100 parts per million

    C

    at least 100 parts per million

    D

    100 parts per million


    正确答案： A
    解析： 暂无解析

  • 第22题：

    单选题
    Sound is audible to human beings only if the frequency is______.
    A

    fewer than about 20 vibrations per second

    B

    more than about 20,000 vibrations per second

    C

    about in a range of 20 to 20,000 vibrations per second

    D

    120 vibrations per second


    正确答案： A
    解析：
    细节题。文章第二段倒数第二句提到“The human ear is usually not sensitive to frequencies of fewer than 20 vibrations per second, or more than about 20,000 vibrations per second”，即“人的耳朵对每秒震动20次以下或2万次以上的声音不敏感”，因此C项正确。

  • 第23题：

    单选题
    A flashing light is a light that（）.
    A

    flashes at regular intervals at a frequency of 120 flashes or more per minute

    B

    is yellow in color

    C

    is visible over an arc of the horizon of not less than 180°nor more than 225°

    D

    All of the above


    正确答案： B
    解析： 暂无解析

  • 第24题：

    单选题
    计算机通信中数据传输速率单位bps代表（）。
    A

     band per second

    B

     billion per second

    C

     bytes per second

    D

    bits per second


    正确答案： D
    解析： 暂无解析

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