如图所示为某学校一套校内备用供电系统,由一台内阻为1Ω的发电机向全校22个教室(

题型:计算题

问题:

如图所示为某学校一套校内备用供电系统,由一台内阻为1Ω的发电机向全校22个教室(每个教室有“220V,40W”的白炽灯6盏)供电。如果输电线的总电阻R是4Ω,升压变压器和降压变压器(都认为是理想变压器)的匝数比分别是1:4和4:1,要求所有灯都正常发光,那么:

(1)发电机的输出功率应是多大?

(2)发电机的电动势是多大?

(3)输电线上损耗的电功率多大?

考点:远距离输电的相关计算
题型:计算题

间距小于20m的平行巷道,其中一个巷道爆破时,两个工作面的人员都必须撤到安全地点。()

题型:计算题

人民法院采取相关措施,方便消费者提起诉讼,属于国家对消费者权益的()。

A.司法保护

B.社会保护

C.立法保护

D.行政保护

题型:计算题

凭证的主附件是以()为单位确定的。

A.柜员

B.机构

C.交易

D.日期

题型:计算题

注入剖面测井的测量方法为示踪法,既利用放射性同位素示踪法测试注入井()。

A、分层采出量

B、全井采出量

C、分层注入量

D、全井注入量

题型:计算题

Ravi, like many project (1) , had studied the waterfall model of software development as the primary software life-cycle (2) . He has all set to use it for an upcoming project, his first assignment. However, Ravi found that the waterfall model could not be used because the customer wanted the software delivered in stages, something that implied that the system had to be delivered and built in (3) and not as (4) . The situation in many other projects is not very different. The real world rarely presents a problem in which a standard process, or the process used in a previous project, is the best choice. To be the most situation, an existing process must be (5) to the new problem. A development process, even after tailoring, generally cannot handle change requests. To accommodate change requests without losing control of the project, you must supplement the development process with a requirement change management process.

空白(1)处应选择()

A.customers

B.managers

C.users

D.administrators

更多题库