题干

二十世纪初,为了研究物质内部的结构,物理学家做了大量的实验,揭示了原子内部的结构。发现了电子、中子和质子,右图是(   )

A:汤姆逊发现电子的实验装置

B:卢瑟福发现质子的实验装置

C:卢瑟福的a粒子散射实验装置

D:查德威克发现中子的实验装置

上一题 下一题 0.0难度 选择题 更新时间:2018-11-25 10:37:15

答案(点此获取答案解析)

C

同类题3

Crazy is our new normal. With two teenage boys and three little boys, our family is restless- to the baseball field, track field (田径场) and piano lessons. Even though we've limited(限制) each boy's activities and try our best to spare some time for the family, it seems that we're always in a hurry.
"Accept it. Roll with it," my husband, Lonny, says, "It's going to be like this for a while."
He is right. It's likely that life will continue to go forward before it slows down. But I remembered the peaceful, quiet days that our family used to enjoy. I missed long walks through the park when we held the boys' little hands. I wished for lazy Saturday afternoons under the tree in our backyard. I wanted to go back a few years, when busyness was the exception and not the rule(惯例).
One night, after a particularly ful day and evening games, our family gathered on the porch (门廊) for ice cream. Two parents, two teens, and three small boys sat on one old swing and a couple of rocking chairs. We were together, in one place, for a short period of time.
The moon was full. The Mississippi River, flowing past our home, was smooth as glass. I put my own arms around the son who sat on my lap and breathed in deeply his little-boy smell -dirt and sweat. My heart was peaceful and satisfied.
I realized that though crazy is our new normal, happiness is as usual. They may look different from before, but they are still there - even if they're in the form of a single moment on the porch. Maybe I just need the eyes to see.