问题
多选题
| 如图为理想变压器原线圈所接交流电压的波形．原、副线圈匝数比n1：n2=10：1，串联在原线圈电路中电流表的示数为1A，下列说法正确的是（ ） A．变压器输出端所接电压表的示数为20 B．变压器的输出功率为200W C．变压器输出端的交流电的频率为50Hz D．穿过变压器铁芯的磁通量变化率的最大值为20  |
V
/n2Wb/s
答案
BCD
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| 如图为理想变压器原线圈所接交流电压的波形．原、副线圈匝数比n1：n2=10：1，串联在原线圈电路中电流表的示数为1A，下列说法正确的是（ ） A．变压器输出端所接电压表的示数为20 B．变压器的输出功率为200W C．变压器输出端的交流电的频率为50Hz D．穿过变压器铁芯的磁通量变化率的最大值为20 |
BCD
| With the understanding of phobias has come a magic bag of treatments: exposure therapy that can stomp out a lifetime phobia in a single six-hour session; virtual-reality programs that can safely simulate the thing the phobia most fears, slowly stripping it of its power to terrorize; new medications that can snuff the brain’s phobic spark before it can catch. In the past year, the U. S. Food and Drug Administration approved the first drug—an existing antidepressant. Most psychologists now assign phobias to one of the three broad categories: social phobias, in which the sufferer feels paralyzing fear at the prospect of social or professional encounters; panic disorders, in which the person is periodically blindsided by overwhelming fear for no apparent reason; and specific phobias—fear of snakes and enclosed spaces and heights and the like. If you are living with a generalized sense of danger, it can be profoundly therapeutic to find a single object on which to deposit all that unformed fear—a snake, a spider and a rat. A specific phobia becomes a sort of backfire for fear, a controlled blaze that prevents other blazes from catching. But a condition that is so easy to pick up is becoming almost as easy to shake, usually without resort to drugs. What turns up the wattage of a phobia the most is the strategy the phobias rely on to ease their discomfort: avoidance. The harder phobics work to avoid the things they fear, the more the brain grows convinced that the threat is real. Progress in treating social-anxiety disorder is also providing hope for the last—and most disabling—of the family of phobias: panic disorder. Panic disorder is to anxiety conditions what a tornado is to weather conditions: a devastating sneaks havoc and then simply vanishes. Unlike the specific phobic and the social phobic who know what will trigger their fear, the victim of panic attacks never know where or when one will hit. Someone who experiences an attack in, say, a supermarket will often not return there, associating the once neutral place with the traumatic event. But the perceived circle of safety can quickly shrink, until sufferers may be confined entirely to their homes. When this begins to happen, panic disorder mutates into full-blown agoraphobia. The treatment for agoraphobia is much the same as it is for social phobia: cognitive-behavioral therapy and drugs. |
The word "blindsided" underlined in Paragraph 3 means ______ .
A．terrorized
B．haunted
C．hit
D．caught