蓄电池充电后即使不用,储存的能量也会逐渐损失,但其电压变化很小,可认为恒定不变.

题型:计算题

问题:

蓄电池充电后即使不用,储存的能量也会逐渐损失,但其电压变化很小,可认为恒定不变.如图是电压为12伏、容量为15Ah的某品牌蓄电池剩余容量随时间变化的图线.现有一只该种蓄电池充足电,存放6个月,用来给额定电压为12伏、额定功率为36瓦的电灯供电.求:

(1)蓄电池容量为“15Ah”,它表示:若该蓄电池以1安的电流为用电器供电,可以工作15小时;则当该蓄电池以2安的电流为用电器供电时,可以工作 _________ 小时.

(2)此灯正常发光时的电流是多少安?

(3)存放6个月的该蓄电池最多可给此灯提供多少焦的电能?

考点:电荷,元电荷,电荷量电功或电能的计算电功率的计算公式的变形
题型:计算题

阅读理解.

    Many places in the world need more fresh(淡的)water. Every country is trying to find ways to turn

salt water into fresh.

   Why aren't there many factories like the Symi factory?

   In some places,the sun isn't hot enough,or it doesn't shine every day. In these places ,other ways of

heating (加热)sea water can be used. These ways cost more money ,but they work faster than the sun.

By boiling (煮沸)sea water with high heat ,a lot of fresh water can be made quickly.

   But heating is not the only way to get fresh water from salt water. Other ways are tried. One way is

freezing (冷冻). The fresh part of salt water freezes first. To get fresh water, the pieces of ice are taken

out. Which way is best? The one that gives the most water for the least money. It may be a different

way for each place. Symi's way seems very good for small, hot places. It doesn't make very much

water at a time. But the factory is easy to build and cost little.

   That's why people in many dry places talk about Symi!

1 .From the passage we know that fresh water ________.

A .is needed in many countries      

B .is needed in every country

C .is very important for factories    

D .is very important for factories

2 .The Symi factory ________.

A .is a fresh-water factory

B .can be built everywhere

C .can make much fresh water at a time

D .doesn't need sunshine every day

3.Which is the best way for small and hot places to get fresh water?

A.Boiling or heating the sea water.

B.The way in sunny places.

C.The Symi's way.

D.Freezing the sea water in cold places.

4.The writer is mainly talking about ________.

A.water-making factories in different countries

B.the ways of making fresh water from sea water

C.hot places and dry places

D.how to make good use of the sunlight

5.Which is wrong?

A.New ways are tried to get fresh water.

B.Heating can make a lot of fresh water quickly.

C.The best way is to get the most fresh water with the least(最少)money

D.The Symi's way doesn't work in dry places .

题型:计算题

目前,光纤的低温特性已达到较好水平,在低温-20摄氏度时,一般光纤损耗增加在()dB/km以下。

题型:计算题

事实上,现代保险业务管理是( )的工作,可以被看成是为被保险人全程服务和提供个性化服务的总目标的组成部分。

A.投保业务
B.将潜在的准客户转化为保险客户
C.找到准客户
D.有针对性的对目标客户进行营销

题型:计算题

某国有公司总经理王某任职期间,公司经营业绩不理想,眼看任期届满难以完成利润考核指标,便找到财务部主任胡某,授意胡某“帮助”改善公司经营业绩。胡某觉得王总经理上任后对自己比较关照,决定“帮”他渡过这一难关。为此,胡某将明年的销售合同提前“发货”,提前开具销售发票,并确认收入。有了这笔“提前收入”的支撑,使得王总经理顺利“完成”了今年的各项利润考核指标任务。

财务部主任胡某提早确认收入的做法,下列说法正确的是( )。

A.胡某是受到总经理王某的授意,故此行为与胡某的职业道德无关

B.胡某的行为属于伪造会计凭证、做假账的行为

C.按照规定,应该对胡某处以5000元以上5万元以下的罚款

D.胡某必须根据实际发生的经济业务事项进行会计核算

题型:计算题

患者,男,声音嘶哑3天,咽喉不适,咳嗽,查双声带红肿,闭合不全,并有发热,恶寒,舌边微红,脉浮数。

首选的外治法为()

A.吹药

B.含漱

C.金黄膏外敷颌下部

D.放脓

E.雾化吸入

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