如图所示的LC振荡电路,在某时刻的磁场方向如图所示,则下列判断不正确的是( )

题型:选择题

问题:

如图所示的LC振荡电路,在某时刻的磁场方向如图所示,则下列判断不正确的是(   )

A.若磁场正在增强,则电场能正在减少,电容器上极板带正电

B.若磁场正在减弱,则电场能正在增强,电容器上极板带正电

C.振荡电流的变化周期为:

D.电场能量的变化周期为:π

考点:麦克斯韦的电磁场理论电磁波
题型:选择题

2003年夏季,我国很多地区出现了电力紧缺的现象.为解决这一问题,我国将加强核能的开发和利用,进一步加快田湾核电站的建设步伐,以满足华东地区不断出现的电荒问题.钚是可用于核电开发的放射性元素,已知钚的相对原子质量为244,核电荷数为94,则它的核外电子数为(  )

A.244

B.160

C.150

D.94

题型:选择题
列竖式计算下面各题.
0.86×7=0.79×4=3.5×16=12.5×42=18.6×23=
0.58×32=0.8×7=2.5×6=2.05×4=12.4×7=
36.8×9=0.7×4=3.6×3=2.3×5=3.3×8=
题型:选择题

沉积学

题型:选择题

B

Societies all over the world name places in similar ways. Quite often there is no official naming ceremony but places tend to be called names as points of reference by people. Then an organized body steps in and gives the place a name. Frequently it happens that a place has two names: One is named by the people and the other by the government. As in many areas, old habits died hard, and the place continues to be called by its unofficial name long after the meaning is lost.

Many roads and places in Singapore(新加坡) are named in order that the pioneers will be remembered by future generations. Thus we have names such as Stamford Road and Raffles Place. This is in keeping with traditions in many countries ---- in both the West and the East.

Another way of naming places is naming them after other places. Perhaps they were named to promote friendships between the two places or it could be that the people who used to live there were originally from the places that the roads were named after. The mystery is clearer when we see some of the roads named in former British bases. If you step into Selector Airbase you will see Piccadilly Circus ---- obviously named by some homesick Royal Air Force personnel.

Some places were named after the activities that used to go on at those places. Bras Basah Road is an interesting example, “Base Basah” means “wet rice” in Malay(马来语). Now why would anyone want to name a road “Wet Rice Road”? The reason is simple. During the pioneering days, wet rice was laid out to dry along this road.

A few roads in Singapore are named by their shapes. There is “Circular Road” for one. Other roads may have part of their names to describe their shapes, like “Paya Lebar Crescent”. This road is called a crescent(月牙) because it begins on the main road, makes a crescent and comes back to join the main road again.

45. We learn from Paragraph 1 that _____.

A. the government is usually the first to name a place

B. many places tend to have more than one name

C. a ceremony will be held when a place is named

D. people prefer the place names given by the government

46. What does the underlined phrase “die hard” in Paragraph 1 probably mean?

A. Change suddenly.                                  B. Change significantly(有重大意义的).

C. Disappear mysteriously.                         D. Disappear very slowly.

47. Which of the following places is named after a person?

A. Raffles Place.                                       B. Selector Airbase.             

C. Piccadilly Circus.                                  D. Paya Lebar Crescent.

48. Bras Basah Road is named _______.

A. after a person           B. after a place              C. after an activity         D. by its shape

题型:选择题

根据冯.诺伊曼思想,计算机内部应采用()表示指令和数据。

A.二进制

B.八进制

C.十进制

D.十六进制

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