在“用电压表和电流表测灯泡电阻的实验”中 (1)实验的原理是: ________

题型:实验题

问题:

在“用电压表和电流表测灯泡电阻的实验”中

(1)实验的原理是: _________

(2)在下面方框中画出实验电路图.并根据电路图在图中将实物电路连接起来.(要求:滑动变阻器的滑片向右移时电流表示数变大)

(3)表中给出了前两次的测量结果,请你依据如图所给的第三次实验中电压表、电流表示数,此时灯泡电阻阻值是: _________ Ω.分析实验数据发现,实验的第一组电阻和第二组电阻值相差近1 Ω,实验过程和读数都没有问题,那么可能的一个原因是: _________

考点:伏安法测电阻电路的连接电路图及元件符号影响电阻大小的因素
题型:实验题

Many theories concerning the causes of juvenile delinquency (crimes committed by young people) focus either on the individual or on society as the major contributing influence. Theories (51) on the individual suggest that children engage in criminal behavior (52) they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through (53) with others. Theories focusing on the role of society suggest that children commit crimes in response to their failure to rise above their socioeconomic status, (54) as a rejection of middle-class values. Most theories of juvenile delinquency have focused on children from disadvantaged families, ignoring the fact that children from wealthy homes also commit crimes. The latter may commit crimes (55) lack of adequate parental control. All theories, however, are tentative and are (56) to criticism. Changes in the social structure may indirectly (57) juvenile crime rates. For example, changes in the economy that lead to fewer job opportunities for youth and rising unemployment (58) make gainful employment increasingly difficult to obtain. The resulting discontent may in turn lead more youths into criminal behavior. Families have also (59) changes these years. More families consist of one-parent households or two working parents; consequently, children are likely to have less supervision at home (60) was common in the traditional family structure. This lack of parental supervision is thought to be an influence on juvenile crime rates.

59().

A.survived 

B.noticed 

C.undertaken 

D.experienced

题型:实验题

在车门报警电路中,两个按钮开关分别装在汽车的两扇门上,只要有开关处于断开状态,报警灯就发光。能实现此功能的电路是

题型:实验题

(4分)如图所示为两种物质的质量和体积的关系图线,根据图线计算:

(1)甲物质和乙物质的密度各为多少kg/m3

(2)2×103cm3的甲物质质量是多少?

题型:实验题

利用三因素法进行固定制造费用的差异分析时,“固定制造费用闲置能量差异”是根据“生产能量”与“实际工时”之差,乘以“固定制造费用标准分配率”计算求得的。 ( )

题型:实验题

某中学生,15岁。经骨髓穿刺检查诊断为"急性淋巴细胞白血病",给以常规治疗,症状无缓解。医生告诉家长,此病目前尚无理想的治疗方法,医院正在尝试使用一种疗效不肯定、有一定风险的药物。其家长表示愿意做这种试验性治疗。但没有履行书面承诺手续。治疗二天后,病人病重,抢救无效,死亡。此后,家属否认曾同意这种治疗方案,称是"拿病人做试验",要追究医生责任,于是造成医疗纠纷。

病人家属称本案是"拿病人作试验"并告上法庭,理由如下,但其真实的思想是()

A.家长没有书面承诺,说明对该方案有保留意见

B.抢救不够及时,拖延了时间

C.家长没签字,医生必须承担患儿死亡的责任

D.要求减免住院费用

E.医生所做的试验缺乏临床数据积累

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