问题
选择题
| 如图所示，矩形线圈有N匝，长为a，宽为b，每匝线圈电阻为R，从磁感应强度为B的匀强磁场中以速度v匀速拉出来，那么，产生的感应电动势和流经线圈中的感应电流的大小应为（ ） A．E=Bav， B．E=NBav， C．E=Bav， D．E=NBav，  |
答案
答案：D
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| 如图所示，矩形线圈有N匝，长为a，宽为b，每匝线圈电阻为R，从磁感应强度为B的匀强磁场中以速度v匀速拉出来，那么，产生的感应电动势和流经线圈中的感应电流的大小应为（ ） A．E=Bav， B．E=NBav， C．E=Bav， D．E=NBav， |
答案：D
| Modem cowboy seem to be giving up the bandanna (印花大手帕) handkerchief; yet there was a time when this article was almost as necessary to a cowboy’s equipment as a rope, and it served for purposes almost as varied. The bandanna made a good sling for a broken arm; it made a good bandage for a blood wound. Early Irish settlers on the Nueces River used to believe that a bandanna handkerchief that had been worn by a drowned man would, if cast into a stream above the sunken body, float until it came over the body and then sink, thus locating the body. Many a cowboy out on the lonely plains has been buried with a clean bandanna spread over his face to keep the dirt, or the coarse blanket on which the dirt was poured, from touching him. The bandanna has been used to hang men. Rustlers used to "wave" strangers around with it as a warning against nearer approach, though the hat was more commonly used for signaling. Like the Mexican sombrero (阔边帽) or the fourgallon Stetson, the bandanna could not be made too large. When the cowboys of the Old West make their final parade on the grassy shores of Paradise, the guidon (旗手) that leads them should be a bandanna handkerchief. It deserves to be called the "flag of the range country". |
The most best title of this passage is ______.
A．Last Roundup
B．Uses of Bandanna
C．Bandits and Bandannas
D．Old West