Electrostatics> when plastic is rubbed with silk cloth .w...

when plastic is rubbed with silk cloth .why electrons move from silk to plastic and not from plastic to silk cloth?

priya , 7 Years ago

Grade 12

3 Answers

Harish

Last Activity: 7 Years ago

Hello Priya !

See your question seems to be somewhat wrong. Because plastic rod and silk cloth both are negatively charged materials. So we can’t predict what will happen when plastic rod is rubbed with silk cloth. This you can also understand by another means that it is the property of charges that like charges repel each other and unlike charges attract each other. So, since both plastic rod and silk cloth are negatively charged materials so they may repel each other and it may not be possible that electrons will flow from one material to another in this case.

However, if your question changes to this that a glass rod is rubbed with silk rod, then electrons flow from glass rod to slik cloth. This is because glass rod is positively charged material so it easily looses its electron and becomes positively charged. Same goes with silk rod. Since it is a negatively charged material , so it easily accepts electron from glass rod .

Hope this helps !

If I am wrong somewhere , please let me know !

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swapnil

Last Activity: 7 Years ago

Because work function of silk cloth is less than that of plastic.Work function of an object is the minimum energy required to take out an electron from that object . When plastic and silk cloth are rubbed together, due to friction, heat energy is produced.Object with lower work function require less energy to loose it`s electron therefore when plastic and silk cloth are rubbed together heat energy reaches work function of silk cloth first so electrons transfers from silk to plastic

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Sabyasachi Choudhury

Last Activity: 3 Years ago

I know it`s too late to help you know, but I`m still leaving this for anyone who might come here.First, take a look at this page - https://www.physicsclassroom.com/class/estatics/Lesson-2/Charging-by-FrictionHere, you`ll notice a think called electron affinity mentioned. Electron affinity, in a nutshell, is just the tendency of a material to take in an electron and hold on to it. High EF means it will absorb electrons, low means it will let a material with higher EF take its electrons.It is this electron affinity which determines which direction the electrons will move when you rub material X with material Y.You might also be wondering how to determine which materials have a higher EF than others. Now, I haven`t found a definitive answer to this from my scouring of the web, but I`ve noticed a pattern - when X and Y are rubbed, its always the one which is a better insulator (or worse conductor), which absorbs the electrons.In other words, higher resistivity = higher electron affinity.Now, I might very well be wrong here, and so feel free to correct me. I hope I could help anyone who comes across this post!