如图所示,电子从灯丝K发出(初速度不计),在KA间经加速电压U1加速后,从A板中

题型:计算题

问题:

如图所示,电子从灯丝K发出(初速度不计),在KA间经加速电压U1加速后,从A板中心小孔射出,进入由M、N两个水平极板构成的偏转电场, M、N两板间的距离为d,电压为U2,板长为L,电子进入偏转电场时的速度与电场方向垂直,射出时没有与极板相碰。已知电子的质量为m,电荷量为e,不计电子的重力及它们之间的相互作用力。求:

(1)电子穿过A板小孔时的速度大小v;

(2)电子在偏转电场中的运动时间t;

(3)电子从偏转电场射出时沿垂直于板方向偏移的距离y。

考点:带电粒子在电场中的加速
题型:计算题

背诵默写

     1. Later, I noticed a tin can (1) ______________upside down on the grill over the fire. After a short

time Tombe threw it (2)_______________the doorway. I was puzzled. Tombe told me that the can was

heated to (3) ______________ the leftover food. They believed that any leftovers attract evil spirits in the nights, so the food is dried up in the can and the can is then thrown out of the hut. (4) ___________ they

don't waste anything.

     2. Xie Lei told me that she feels much more (5) ______________ in England now, and what had

seemed very strange before now appears quite (6) _________. "I've just got one more thing to achieve.

I have been so (7) _________________work that I haven't had time for (8) _________ activities. I think it's important to have a (9) _________ between study and a social life, so I'm going to join a few clubs.

(10) _____________ I'll make some new friends."

题型:计算题

红霉素与口服避孕药联用时降低避孕效果其原因是

A.抑制肝药酶使其不能正常代谢

B.影响口服避孕药的吸收

C.改变肠道菌群

D.促进口服避孕药的代谢

E.影响口服避孕药的血药浓度

题型:计算题
—Could I please go to the movies?
—Yes, ______.

A. you can
B. you could
C. you do
D. you are
题型:计算题

虚劳病的基本病机为()

A.气血阴阳失调

B.气血阴阳亏虚,脏腑功能失调

C.气血阴阳亏虚,脏腑虚损

D.阴阳失调,营卫不和

E.脏腑功能失调

题型:计算题

板材的冲裁分离有哪两类?各有什么不同?

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