UC知道英语阅读理解 在线等 急急急
来源：百度知道 编辑：UC知道 时间：2024/05/28 05:22:42
Under proper conditions, sound waves will be reflected from a hillside
or other such obstruction. Sound travels at the rate of about one-fifth of
a mile per second. If the hill is eleven hundred feet away, it takes two
seconds for the sound to travel to the hill and back. Thus, by timing the
interval between a sound and its reflection (the echo), you can estimate the
distance to an obstruction.
During World War II, the British used a practical application of this
principle to detect German planes on their way to bomb London long before
the enemy was near the target. They used radio waves instead of sound
waves, since radio waves can go through fog and clouds. The outnumbered
Royal Air Force (RAF) always seemed to the puzzled Germans to be lying in
wait at the right time and never be surprised. It was radio echoes more
than anything else that won the Battle of Britain.
Since the radio waves were used to te
or other such obstruction. Sound travels at the rate of about one-fifth of
a mile per second. If the hill is eleven hundred feet away, it takes two
seconds for the sound to travel to the hill and back. Thus, by timing the
interval between a sound and its reflection (the echo), you can estimate the
distance to an obstruction.
During World War II, the British used a practical application of this
principle to detect German planes on their way to bomb London long before
the enemy was near the target. They used radio waves instead of sound
waves, since radio waves can go through fog and clouds. The outnumbered
Royal Air Force (RAF) always seemed to the puzzled Germans to be lying in
wait at the right time and never be surprised. It was radio echoes more
than anything else that won the Battle of Britain.
Since the radio waves were used to te
自己做吧
在适当的条件下,声波会从山坡上
或其它类似的阻塞。声音传播速度大约五分之一
每秒一英里。如果那山地容一千一百英尺远的地方,它需要两个人
秒钟去山上声音才回来。因此,通过时间的
间隔一声和反射(回声),你可以估计
距离受阻。
在第二次世界大战中,英国使用的实际应用
探测原理,在德国飞机轰炸伦敦之前的很长一段时间
敌人已接近目标。他们用无线电波相反的声音
波浪,自从无线电波能穿过雾和云。这个数量
皇家空军(英国皇家空军)似乎总是当德国人要躺在
在正确的时间和不会感到惊讶。它是广播回声
比其它任何打赢了一仗。
自从无线电波被用来告诉方向发送
英国皇家空军飞机和距离寄给他们(他们的飞行,在
换句话说,他被称为无线电设备和检测,并从
第一个字母的单词是杜撰的雷达。
6。声波反射出一个小山可以用来估计__ _____。
一)强B)距离山顶
C)声速D)高度的山
7。在第二次世界大战中,英国用__ _____侦测到德国
飞机。
一)无线电检测和设备B)电子声波的装置
C)的新电子仪器设备购置飞机D)的新收音机为空军
8。雷达使英语到_____ ___。
一)混淆的德国轰炸机飞行员B)的英国皇家空军飞机的情况下有效地检测
C)探测德国飞机赶往伦敦D)和A和B
9。为什么英国使用无线电波吗
一),因为他们更精确比声波。
B),因为它们不能被发现。
因为他们是更容易使用,比声波。
D),因为他们可以透过雾和云。
10。师:从这篇文章
一)雷达是一家著名的实际应用的原则。
B)光波也可以用于雷达装置相似。
C)雷达大大增加了皇家空军的有效性。
D)声波反射下山坡上的所有条件。<