问题
选择题
| 在均匀介质中选取平衡位置在同一直线上的9个质点，相邻两质点的距离均为L，如图甲所示．一列横波沿该直线向右传播，t=0时到达质点1，质点1开始向下运动，经过时间△t第一次出现如图乙所示的波形．则该波的（ ） A．周期为△t，波长为8L B．周期为 C．周期为 D．周期为△t，波速为 |
，波长为9L
答案
答案：C
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| 在均匀介质中选取平衡位置在同一直线上的9个质点，相邻两质点的距离均为L，如图甲所示．一列横波沿该直线向右传播，t=0时到达质点1，质点1开始向下运动，经过时间△t第一次出现如图乙所示的波形．则该波的（ ） A．周期为△t，波长为8L B．周期为 C．周期为 D．周期为△t，波速为 |
答案：C
| 完形填空。 | ||||
| Gold Mine in Scotland If you were interested 1 a gold miner, you would probably not think 2 to Scotland to begin your career. But 3 a gold rush in Scotland a hundred years ago, even though it only lasted 4 a short time. The 5 thing about this gold rush was that the man who started it, a Mr. Gilchrist, 6 back from Australia after 7 many years looking for gold without success. 8 , while he was standing on a bridge near his home, he 9 that the stream was shining brightly. He 10 surprised to realize that the gold he had been looking for 11 long time was on his doorstep, so to speak. He 12 to work immediately but he soon told his neighbours about this good 13 and hundreds of men 14 the village, hoping to make their fortunes, too. After a year or so, the gold had gone and 15 but expeditions have been formed 16 since then to see where the gold comes from. So far 17 18 find the source and interest has died down 19 the greater attractions of the "black gold" off the Scottish coast, the oil recently discovered in the North Sea which 20 to provide Scotland with great wealth in the future. | ||||
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