问题 单项选择题 A1/A2型题

X线机对接地电阻的要求是()

A.<8Ω

B.<4Ω

C.<6Ω

D.<7Ω

E.<5Ω

答案

参考答案:B

解析:X线机接地装置由接地极和连接导线组成,总接地电阻要求小于4Ω。

材料分析题

2009年水污染事件:因韶关冶炼厂设备检修期间超标排放含镉废水,导致北江韶关段镉严重超标,严重威胁下游饮用水源安全;山东胶州村庄因企业违法排污,水源受污染,五年20余人患癌症,同时大多数村民家的井水都因含很多杂质而无法饮用;由于自来水水源受到化工污染,江苏省盐城市区发生大范围断水,至少20万居民的生活受到影响。

(1)请你结合材料多角度分析水污染事件频繁发生的原因。

                                                                                                                                                                

                                                                                                                                                              

(2)为减少水污染事件的频繁发生,请你提出几条可行性建议。

                                                                                                                                                               

                                                                                                                                                               

(3)有人认为,要加快经济发展就必然会破坏环境,注重了环境保护就会影响当地经济的发展。这种观点对吗?为什么?

                                                                                                                                                              

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                              

单项选择题