【简答题】两相干点波源s 1 和s 2 , φ 1 ,初相差φ 2 -φ 1 =π,p点位于过s 1 点且垂直s 1 s 2 的直线,φ 2 =0.4m,如图所示,如果要使波源发出的波在p点产生相长干涉,两波长应满足的条件为______。(k=1,2,…,n)
【多选题】图示某汽油车电源系统中,蓄电池充满电且处于室温状态,当发动机静止且点火开关处于ON挡时,点火开关1号接线柱与 接线柱接通,指示灯应 ,表明发电机 发电,发电机端电压为 V。发动机起动后,松开点火开关,点火开关处于 挡。发动机中高速运转时,指示灯应 ,发电机端电压应达到 V,发电机N、E接线柱间的电压应达到 V。当发电机端电压达到14.5V时,调节器 接线柱与 接线柱间应 ,当发电机端电压低于13....
【判断题】K线理论发源于美国,是最古老的技术分析方法
【单选题】In the future trade the key development to watch is the relationship between the industrialized and the developing nations. The【C1】______World Countries export their mineral【C2】______and some agricult...
【单选题】若发生 1 号变桨电机发生过热故障,且问题确认存在于散热风扇电路,滑环接入电源正常, 16K5 得电线圈吸合,但散热风扇接入电源检测为U12=380V、U13=190V、U23=190V,那么故障范围应该存在于
【简答题】海鲜馆里有一道菜叫“西施舌(一种软体动物)炒九层塔(一种香料植物)”媒体报道九层塔含有黄樟素。(甲)小明认为微量黄樟素会导致癌症;(乙)于是,他准备了两组老鼠,一组长期喂含有微量黄樟素的食物,另一组喂正常食物;(丙)一年后,两组老鼠都没患癌症。 (1)上文步骤(甲)应属于科学探究方法的哪一步。答________________。 (2)当实验结果不符合假设时,说明假设是_______(填正确或错误...
【多选题】瞬间光源指采用电子闪光灯发出的光源,下列属于瞬间光源的特性的是( )
【单选题】With which of the following statements regarding the behavior. of large firms in industrialized societies would the author agree?
A.
The directors of large firms will continue to anticipate the demand for products.
B.
The directors of large firms are less interested in achieving a predictable level of profit than in achieving a large profit.
C.
The directors of large firms will strive to reduce the costs of their products.
D.
Many directors of large firms believe that the government should establish the prices that will be charged for products.