问题 计算题

在匀强磁场中,有一根长1m的通电导线,导线中的电流为0.5A,这根导线与磁场方向垂直时,所受的安培力为2×10-2 N,求:

(1)磁感应强度的大小;

(2)2cm的导线所受到的安培力为2×10-4 N,导线中的电流为多少?

(3)这根导线与磁场方向平行时,所受的安培力。

答案

(1)10-2T

(2)1A

(3)0

单项选择题 A1型题
单项选择题

Many researchers have found greater dependence and obedience in very young girls, greater autonomy and activity in boys. When a barrier is set up to separate children from their mothers, boys try to knock it down; girls cry helplessly. There is little doubt that mother’s encouragement or discouragement—of such behavior plays a major role in determining adult personality. For example, a mother often stimulates male autonomy by throwing a toy far away from her young son, thus silently suggesting to him that he leaves her to get it.
Animal studies suggest that there may be a biological factor in material behavior; mothers of some monkeys punish their male babies earlier and more often than their female offspring; they also touch their female babies more often and act more protectively toward them.
As for the controversial question of female "passivity", psychologist Helen Deutsh believes that the concept has been misunderstood. "There is no contradiction between being feminine and working. The self can be active in both men and women," she says. It is only in love and sex that passivity is particularly appropriate for women. As she sees it, passivity is no more than a king of openness and warmth; it does not mean "inactivity of emptiness".
Another controversy ranges over the effect of hormones. Aggressive women; who discount hormonal influence, disagree violently with scientific researchers, who almost unanimously agree that hormones help determine how people feel and act. So far, there have been few studies of male hormones, but scientists think they may eventually discover hormonal cycles in men that produce cyclic changes in mood and behavior. As for females, studies have indicated that 49 percent of female medical and surgical admissions, most psychiatric hospital admission and 62 percent of violent crimes among women prisoners are related with hormonal cycles in women.

Which of the following is NOT true according to the passage

A.Throwing away a toy from her kids is an act worth following.

B.Kids should be encouraged to do things independently.

C.A mother who cries often before kids may lead to dependence of her kids.

D.A mother should not expose her depression too much in front of her kids.