首页
登录
职称英语
Noise enters our ears as powerful waves of mechanical energy. Scientists mea
Noise enters our ears as powerful waves of mechanical energy. Scientists mea
游客
2023-09-11
84
管理
问题
Noise enters our ears as powerful waves of mechanical energy. Scientists measure sound intensity in decibels (db), with each doubling of energy adding ten decibels. Ordinary conversation measures about 60 db; a child’s scream hits around 90 db. On this logarithmic scale, the scream is potentially 1,000 times more powerful.
Each day, over five million Americans are exposed on the job to at least 90 db, the maximum safe level for an eight-hour period according to the federal Occupational Safety and Health Administration. "This standard isn’t ideal, because noise affects individuals differently," says William Clark of Washington University’s Central Institute for the Deaf in St. Louis. "In theory, the standard should protect the lifetime hearing ofg0 percent of workers. However, it assumes that a worker’s ears will have 16 hours of quiet each day during which to recover -- an unlikely assumption for most people."
Sound causes thousands of tiny hairs in the inner ear to vibrate. These vibrations trigger nerve impulses to the brain, which are perceived as sound. Prolonged exposure to 85 db or more, or far shorter exposure to very intense levels -- such as the 140-db shock waves from a shotgun blast -- can irrevocably damage some of these delicate inner-ear hairs. Ronald Reagan suffered permanent injury during his acting days when a 38-caliber pistol loaded with blanks was fired near his right ear. As a result, he now wears a hearing aid. Audiologists predict that by the year 2000, as many people could be wearing hearing aids as now wear contact lenses.
Many people believe that weaker hearing is an inevitable part of aging. But studies show that those who live in low-noise environments tend to have very little hearing loss in old age.
In noisy industrial nations, however, even young people suffer damaged hearing. David Lipscomb, a former professor of audiology at the University of Tennessee at Knoxville, tested over a thousand incoming freshmen and discovered that six of every ten had heating loss typical of the elderly. Rock music is one cause. The noise in a reek-concert hall can easily exceed 120 db, roughly the level of an air-raid siren. High-tech gadgets such as powerful portable stereos also threaten to put our hearing into a downward spiral. [br] Why does Ronald Reagan have to suffer permanent injury of heating? Because _______.
选项
A、his tight ear has been damaged
B、his nerve system is inefficient
C、there is some problem with his brain
D、some of the delicate hairs in his inner ear have suffered a great damage
答案
D
解析
第三段说里根做演员的时候有人以一支38毫米口径的枪在他右耳附近开了枪,他的听力因此受损。听力受损时其实是内耳里细微的小茸毛受了伤害,而不是脑子或神经的问题。也可能这方面的损伤对听力也有影响,但这不在本篇的范围内,本篇也未提,因此答案为D。
转载请注明原文地址:https://tihaiku.com/zcyy/3005147.html
相关试题推荐
[originaltext]Ifwinningiseverything,Britishscientistshavesomeadvice
[originaltext]Ifwinningiseverything,Britishscientistshavesomeadvice
[originaltext]Scientistssaythatmostdoctorsandpatientsalreadyknowwh
[originaltext]Scientistssaythatmostdoctorsandpatientsalreadyknowwh
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
ScientistssaythewarmingoftheEarth’satmospherehasbeguntoaffectpla
随机试题
情景:你们戏剧小组(dramagroup)要举行会议来讨论“英语之夜”出演的戏剧(play)。任务:请你就此用电子邮件给王教授写一封50词左右的邀请
Thepresident’s______remarksinhisspeechmetwithalotofattacksfromothe
Allofthefollowingaretrueexceptthat______.[br]Thosewhoviolatedthera
肾上腺素的生理作用包括()。A.使心跳加快,心肌收缩力增强,心输出量增加
A.f(-x,y)=f(x,y),f(x,-y)=-f(x,y) B.f(-x
狂犬病患者咽肌痉挛发作最常见的诱发因素是()。A.流水声 B.强光 C.噪
A. B. C. D.
下列关于流动性比例的叙述中,错误的是()。A.流动性比例的计算公式为:流动性比例
共用题干 一般资料:求助者,男性,21岁,大学三年级学生,因担心毕业找不到工作
女,36岁。因急性一氧化碳中毒入院,治疗1周后症状消失出院。2月后突然出现意识障
最新回复
(
0
)