本题目来源于试卷: Electric Charge and Electric Field，类别为 IB物理学
[问答题]
Why does a plastic ruler that has r qlm idqax9wj698::y+vo2t /7 jpmkwbeen rubbed with a cloth have the abzi1m:zyct:f) ility to pick up small pieces of paper? Why isftc:)1 zzi:m y this difficult to do on a humid day?
参考答案: The plastic ruler has gained some
electrons from the cloth and thus has a net negative charge. This charge polarizes the charge on the piece
of paper, drawing positives slightly closer and repelling negatives slightly further
away. This polarization results in a net
attractive force on the piece of paper.
A small amount of charge is able to create enough electric force to be
stronger than gravity, and so the paper can be lifted. On a humid
day this is more difficult because the water molecules in the air are
polar. Those polar water molecules are
able to attract some fraction of the free charges away from the plastic
ruler. Thus the ruler has a smaller
charge, the paper is less polarized, and there is not enough electric force to
pick up the paper.
本题详细解析:
暂无
| 
